Are you ready to upgrade your smartphone? If yes, then you have come to the right place. In this nifty guide, we will help you decide on your smartphone. Thanks to some exciting smartphone launches from Asus, Vivo, and Nokia (HMD Global), buying a premium smartphone no longer requires you to shell out a significant sum of money. With refinements in the smartphone technologies over the years, the phones priced under Rs.30,000 no longer look like the inferior versions of their flagship counterparts. There are currently some very interesting phones in Rs. 25,000 to Rs. 30,000 price bracket, ranging from phones with in-display fingerprint sensors to mobiles with flagship-grade processors and multiple camera setups.
All the smartphones listed below have gone through our usual set of performance tests and have earned a place in this list. So, without any more delay, here’s a look at our top picks for best mobiles under Rs. 30,000.
12. Nokia 7.2
The Nokia 6.1 Plus was launched in August 2018 is one of the best mid-range offerings from Nokia. The phone packs 5.8-inch IPS display with Corning Gorilla Glass 3 protection and there is a tiny notch at the top. The screen has a resolution of 1080x1920 pixels.
The dual-SIM Nokia 6.1 runs on top of Android 8.0 (Oreo) out of the box and is upgradeable to the latest Android Pie. It is powered by the octa-core Snapdragon 636 SoC from Qualcomm coupled with 4GB of LPDDR4 RAM and has a 64GB of onboard storage. There is a dual rear camera at the back of 16 MP (f/2.0, 1.0µm, EIS) and 5 MP (f/2.2, 1.2µm) and for the selfie, there is the 16MP shooter at the front.
Nokia 7.2 Specifications
- Display: 6.3" Full HD+ IPS PureDisplay, resolution of 1080 x 2280 pixels, 19:9 aspect ratio
- CPU: Qualcomm Snapdragon 660
- GPU: Adreno 512
- RAM/ROM: 4/64GB, expandable up to 512GB via MicroSD Card
- Rear Camera: 48MP ½” Quad Pixel main sensor, 5MP Depth Sensor and 8MP ultra-wide lens, LED FLash
- Front Camera: 20MP Quad Pixel Selfie shooter
- OS: Android 9.0 Pie
- Audio: 3.5 mm headphone jack, Qualcomm® aptX™ audio, FM radio, 2 microphones with spatial surround sound capture
- Sensors: Ambient light sensor, RGB sensor, Proximity sensor, Accelerometer (G-sensor), E-compass, Gyroscope
- SIM: Dual Nano-SIM
- Nokia 7.2 Price in Nepal: Rs. 23,999 (Available at durbarmart )
11. Honor 9X
Honor 9X is the first phone on this list from Honor. The 9X is the latest handset from Honor in Nepal which comes with the motorized pop-up selfie camera, a huge amount of RAM and storage and good battery life. The phone packs 6.59″ LTPS IPS LCD screen with the resolution of 1,080 x 2,340px. There is a triple camera setup at the back with – 48+8+2 MP lenses and 16MP front camera for the selfies.
The phone is powered by Kirin 710F chipset and coupled with 6GB of RAM and 128GB of storage. The huge 4000mAh battery fuels the 9X. The price of Honor 9X in Nepal is Rs. 29,999 for 6/128GB variant.
Honor 9X Specifications:
- Body: 6.42 x 3.04 x 0.35 inches; 206 gm; front/back glass
- Display: 6.59-inches IPS LCD panel
- Resolution: Full-HD+ (2340 x 1080 pixels); 19.5:9 aspect ratio
- Chipset: HiSilicon Kirin 710F; 12nm Mobile Platform
- CPU: Octa-core (4×2.2 GHz Cortex-A73 & 4×1.7 GHz Cortex-A53)
- GPU: Mali G51 MP4
- RAM: 6GB
- Storage: 128GB (expandable up to 512GB)
- Software & UI: Android 9.0 (Pie) with Huawei’s EMUI 9.1 on top
- Rear Camera: Triple-camera; 48MP f/1.8 primary sensor, 8MP f/2.4 ultrawide lens, 2MP f/2.4 depth sensor
- Front Camera: 16MP, f/2.2 aperture (motorized)
- Fingerprint sensor: Physical (rear-mounted)
- Connectivity: Dual-SIM (Nano), WiFi 802.11 a/b/g/n/ac, Bluetooth 5.0, AGPS/GPS/GLONASS/BDS, USB Type-C, 3.5mm headphone jack
- Battery: 4000 mAh battery with 10W Charging
- Colors: Midnight Black, Sapphire Blue
- Honor 9X Price in Nepal: Rs. 29,999 (6/128GB) (Available at durbarmart )
10. OPPO F11
Oppo F11 Pro is an amazing device and the vanilla F11 shares most of the niceties with its “Pro” variant. With the recent price drop, the Oppo F11 is available in Nepal under Rs. 30,000. Hence, its a decent choice for this price range.
The phone comes with an appealing design. Although it wrapped around with plastic material, it feels as premium as a glass back. And with the triple-tone color gradient, the handset looks quite stunning.
The Helio P70 processor is also a capable chipset at this price. So the performance is quite smooth. And with the 4GB RAM on the board, you can also multitask between a number of apps without an issue. But while playing graphics-enriched games like PUBG, you can get smooth performance only at low settings. On high settings, you will start to notice some stutters.
Cameras on the Oppo F11 are impressive. Be it a normal image, portrait or selfies, you get decent colors and sharpness. However, the images look overprocessed at times. And the lack of ultra-wide-angle lens is dearly missed on this device.
Battery life is decent on the device and you also get a fast charger inside the box. So there is nothing to worry about that part. But there is still Micro USB port, which looks quite outdated these days.
OPPO F11 Specifications:
- Display: 6.53-inch LTPS IPS LCD Full HD+ display, 19.5:9 aspect ratio
- CPU: Octa-core MediaTek Helio P70
- PU: Mali-G72 MP3
- OS: Android 9 Pie with ColorOS 6 on top
- RAM: 4GB
- Storage: 128GB, Expandable up to 256GB via SD card
- Rear Camera: Dual: (48MP, f/1.8, 1/2″, 0.8µm, PDAF) + (5MP, f/2.4, 1/5”, 1.12µm), LED flash
- Front Camera: 16MP selfie camera, f/2.0
- Sensors: Fingerprint (Rear-mounted), Accelerometer, Gyro, Proximity, Compass
- Battery: 4,000 mAh with VOOC 3.0 Flash Charging technology; Micro USB charging port
- OPPO F11 Price in Nepal: Rs. 29,990
9. Mi A3
Mi A3 is the successor of popular Mi A2 phones that comes with Android One OS. The handset is also one of the latest phones in Nepal from Xiaomi. Mi A3 packs great features and comes at competitive pricing. The only downside of this device is, it packs 720p display which doesn’t seem reasonable for Xiaomi. If it had 1080p or better display, it would be the best phone under 30000 in Nepal.
Powered by SD 665 chipset, Mi A3 also comes on two variants of RAM and storage. The 4/64GB model and 6/128GB variant. The great aspect of this device is its software – Stock Android 9.0 (Pie) based on Android One. Featuring a triple 48MP AI camera at the back, it also houses a 32MP AI selfie camera at the front. The price of Mi A3 in Nepal is Rs. 23,999 for 4/64GB model and Rs. 27,999 for 6/128GB model.
Technical Specifications of Mi A3
- Display: 6.08-inch Super AMOLED with Corning Gorilla Glass 5 protection
- Resolution: HD+ (720 x 1560 pixels); 19.5:9 aspect ratio @286PPI pixel density
- Chipset: Snapdragon 665; 11nm Mobile Platform
- CPU: Octa-core 2.0 GHz Kryo 260
- GPU: Adreno 610
- RAM: 4/6GB
- Storage: 64/128GB; expandable memory up to 256GB with micro SD
- Software & UI: Stock Android 9.0 (Pie)
- Rear Camera: Triple Camera setup – (48MP primary camera, f/1.8 aperture, PDAF) + (8MP ultra-wide-angle) + (2MP depth sensor), LED flash
- Front Camera: 32MP, f/2.0
- Sensors: Fingerprint (under display), accelerometer, gyro, proximity, compass
- Battery: 4030mAh battery with 18-watt fast charging
- Mi A3 Price in Nepal: Rs. 23,999(4/64GB) | Rs. 27,999(6/128GB
8. Vivo S1
Cameras have always been a strong suit of all the Vivo phones and that continued on the Vivo S1 as well. The phone captures amazing images with a sufficient amount of details, great colors and a good dynamic range. Portrait and wide-angle images are also quite noteworthy. Talking about the selfies, they have a good balance of colors and maintain exposure levels very well. However, the skin tone doesn’t look very natural.
As for the battery, the 4500mAh battery provides an enduring battery life. In that context, the Super AMOLED display is also power-efficient due to which the battery backup extends even further. As for the performance, the Helio P65 processor lets you PUBG smoothly at low settings. And that’s understandable for the price.
However, the phone comes with a Micro USB port, which is turning obsolete these days. Also, using the FunTouch OS is no fun at all. The UI on the device is a blatant copy of the iPhone, which may not be everyone’s cup of tea.
Vivo S1 Specifications:
- Display: 6.53″ (1080 x 2340 pixels) Super AMOLED
- Rear Camera: Triple, 16 MP (f/1.78) primary + 8 MP (f/2.2) ultrawide + 5 MP depth sensor (f/2.4)
- Front Camera: 32 MP (f/2.0)
- Processor: MediaTek Helio P65
- CPU: Octa-core (2×2.0 GHz Cortex-A75 & 6×1.7 GHz Cortex-A55)
- RAM: 4/6GB
- Storage: 128 GB onboard, expandable up to 256 GB
- OS: Android 9.0 Pie, FunTouch OS 9
- Battery: 4500 mAh, 18W Fast Charging
- Sensors: UD Fingerprint, accelerometer, gyro, proximity, compass
- Vivo S1 Price in Nepal: Rs. 28,390 (4/128GB) | Vivo S1 (6/128GB) Rs. 31,490
7. Redmi Note 7 Pro
Redmi Note 7 Pro is one of the best selling phones in Nepal. The device was once the best phone under Rs. 30000 here in Nepal but later after the price drop of other phones, they took the position of this device. Altogether there are three variants of Redmi Note 7 Pro – 4/64GB, 6/64GB and 6/128GB in Nepal.
Redmi Note 7 Pro packs 6.3″ FHD+ (2340×1080) LTPS display with a 19.5:9 aspect ratio. Protected by Gorilla Glass 5 on front and back, the handset has a tiny waterdrop notch at the top. It is protected by Qualcomm Snapdragon 675 Octa-Core SoC which is also found on Galaxy M40. The price of Redmi Note 7 Pro is Rs 23,999 for 4GB/64GB, 24,999 for 6GB/64GB and Rs. 25,999 for 6GB/128GB variant.
Technical Specifications of Redmi Note 7 Pro
- Display: 6.3″ FHD+ (2340×1080) LTPS display, 19.5:9 aspect ratio, Gorilla Glass 5
- Rear Camera: 48MP f/1.79, 1/2″ sensor, IMX586; 5MP depth sensor
- Front Camera: 13MP selfie
- CPU: Qualcomm Snapdragon 675 Octa-Core SoC; 2xA76 email@example.comGHz, 6xA55 firstname.lastname@example.orgGHz; 11nm process
- GPU: Adreno 612
- RAM: 6GB/4GB
- Storage: 128GB/64GB
- Battery: 4000mAh; 18W fast charger support (10W included in the box)
- Ports: USB Type-C, 3.5mm headphone jack
- OS: Android Pie with MIUI 10 on top
- Colors: Neptune Blue, Nebula Red, Space Black
- Redmi Note 7 Pro Price in Nepal: Rs 23,999 (4GB/64GB) | 24,999(6GB/64GB) | 25,999 (6GB/128GB)
6. Realme 5 Pro
And marking the first and only entry for Realme on the list is the Realme 5 Pro. With the budget and mid-range market so dominated by the likes of Redmi and Samsung, OPPO’s sub-brand Realme has been coming up with great phones in the very price range. Here, the Realme 5 series is definitely what put the company in the map (with over 5.5 million units sold) – and the top-end phone on the series is the Realme 5 Pro.
The main attraction of the phone is definitely its cameras and performance. Talking about the camera, you get the 48MP Sony IMX586 sensor, which was found in most premium phones in 2018 and 2019. Besides that, there’s an 8MP ultrawide lens, a 2MP macro sensor for close-subject photography, and a 2MP depth sensor. Realme 5 Pro doesn’t have a pop-up mechanism, so it’s got a 16MP Sony IMX471 selfie shooter inside a waterdrop notch.
Another great thing about the Realme 5 Pro would be its performance. It is powered by the Snapdragon 712, which is a great mid-range SoC. Everyday tasks run smoothly with no problem, and you can even play graphic-intensive games like Call of Duty and PUBG in moderately high settings, with no stutter. The phone is available in 4/128GB and 8/128GB variants in Nepal.
Realme 5 Pro is a visual treat as well, as it has a stunning diamond-shaped pattern on the back, that reflects differently depending upon how the light hits the surface.
Realme 5 Pro Specifications:
- Display: 6.3 inches FHD+ Full HD+ display, Corning Gorilla Glass 3+ protection
- Design: Crystal Design (Nano-Holographic Color)
– 48MP primary camera with 1/2.0″ Sony IMX586 sensor, 0.8μm pixel size, f/1.79 aperture, LED flash, EIS,
– 8MP 119° ultra-wide-angle lens with f/2.25 aperture, 1.12μm pixel size
– 2MP for 4cm macro with f/2.4 aperture, 1.75μm pixel size
– 2MP depth sensor
- Front Camera: 16MP with Sony IMX471 sensor
- Processor: Qualcomm Snapdragon 712
- CPU: Octa-core (6 x Kryo 360 Silver at 1.7GHZ and 2 x Kryo 360 Gold at 2.3GHz)
- GPU: Adreno 616
- RAM: 4/6/8 GB
- OS: Android Pie (Color OS 6)
- Storage: 64/128 GB onboard, expandable up to 256 GB, dedicated slot
- Battery: 4035 mAh non-removable with VOOC Flash Charge 3.0
- Sensors: Accelerometer, proximity, compass, fingerprint
- Realme 5 Pro Price in Nepal: Rs. 26,990 (4/128GB)
5. Samsung Galaxy M40
Samsung Galaxy M40 is one of the best phones in Nepal that is priced under Rs. 30,000. The display and the battery were the major highlights on the handset. Galaxy M40 comes with a more capable processor and a better design as compared to similarly priced Galaxy A50.
The Galaxy M40 packs 6.4 inches Full HD+ display with a resolution of 2400 x 1080 pixels. The IPS panel has a tiny punch hole for the selfie camera at the top right corner. The device is powered by octa-core(2 x 2.0 GHz + 6 x 1.7 GHz), Snapdragon 675 chipset and is coupled with 6GB of RAM. The phone has ample storage of 128GB in this price segment of 30K. It also features triple camera setup – 32 megapixel (f / 1.7, autofocus) + 8 megapixel wide-angle (f / 2.2, 123 degrees) + 5 megapixel depth (f / 2.2) on the back and 16MP sensor on the front.
Furthermore, there is a fingerprint scanner at the back, a speaker built into the screen and a good enough battery of 3500mAh. The phones also support fast charging at 15W. With all these features the phone is certainly one of the best smartphones under Rs. 30000 in Nepal. It is priced at Rs. 29,990 for the 6/128GB variant.
Technical Specifications of Galaxy M40
- Display: 6.4 “, 19: 9, Full HD +, 2400 x 1080 pixels, IPS
- Platform: Android 9 Pie with One UI
- Rear Camera: Triple Setup, 32 megapixel (f / 1.7, autofocus) + 8 megapixel wide-angle (f / 2.2, 123 degrees) + 5 megapixel depth (f / 2.2), LED flash
- Front Camera: 16 megapixel, f / 2.0, In-display hole
- Processor: 8 cores, 2 x 2.0 GHz + 6 x 1.7 GHz, Snapdragon 675
- RAM: 6 GB LPDDR4X
- Memory: 128 GB, microSD (up to 512 GB)
- Connectivity: A-GPS, GLONASS, Beidou, Bluetooth 5.0 LE, NFC, Wi-Fi 802.11a/b/ g/n/ac, 2.4/5 GHz , USB Type-C
- Others: Fingerprint scanner, Speaker built into the screen
- Battery: 3500 mAh, fast charging 15W
- Galaxy M40 Price in Nepal: Rs. 25,999(6/128GB)
4. Samsung Galaxy M30s
Samsung Galaxy M30s definitely comes under the best smartphone under 30000 and here are some reasons for it. Samsung is rocking the budget phone segment with it's M series and A series. Samsung Galaxy M30s features a 6.4-inch Super AMOLED display with Full HD+ resolution, (2340×1080 pixels) with aluminum frame and a plastic body on back and front. It features a triple-camera setup of 48MP rear camera with LED flash, f/2.0 aperture, 5MP depth sensor with f/2.2 aperture, 8MP ultra-wide-angle camera with f/2.2 aperture with Exynos 9610 chipset. The price of M30s in Nepal is Rs. 24,899 for 4/64GB. The best part of Galaxy M30s is its massive 6000mAh battery.
Samsung Galaxy M30s Specifications:
- Display: 6.4 inches super AMOLED Full HD+ screen with 1080 x 2400 resolution Full HD+ Infinity-U Super AMOLED display
- Chipset: Exynos 9610 (10nm)
- CPU: Octa-core (4x2.3 GHz Cortex-A73 & 4x1.7 GHz Cortex-A53)
- GPU: Mali-G72 GPU
- RAM & Storage: 4GB RAM with 64GB storage / 6GB RAM with 128GB Storage, expandable up to 1TB via micro SD card
- OS: Android 9.0 (Pie) with One UI
- SIM: Dual SIM
- Back Camera: 48MP rear camera with LED flash, f/2.0 aperture, 5MP depth sensor with f/2.2 aperture, 8MP ultra-wide-angle camera with f/2.2 aperture
- Front Camera: 16 MP, f/2.0
- Battery: 6000mAh battery with 15W fast charging
- Galaxy M30s Price in Nepal: Rs. 28,699(6/128) | Rs. 24,899(4/64GB)
3. Redmi Note 8 Pro
Redmi Note 8 Pro is definitely the best smartphone that is priced under Rs. 30,000 in Nepal. This device is also the latest offering from Xiaomi Nepal along with Redmi Note 8. Redmi Note 8 Pro is the successor of one of the bestselling Redmi Note 7 Pro which is still trending in the market.
Redmi Note 8 Pro packs 6.53-inch IPS LCD screen with a resolution of 2340×1080 pixels and is protected by Corning Gorilla Glass 5 protection on both front and back. The Quad Camera setup on it is really impressive with its primary sensor of 64MP and other 8+2+2 MP camera setup with different capabilities.
The device is powered by Helio G90T (2 x 2.27GHz Cortex A76 + 6 x 1.7GHz Cortex A55) which is a gaming-centric chipset. The phone is available in three variants of 6/64, 6/128, 8/128GB and the price of the handset is Rs. 26,999, 29,999 and 32,999 respectively.
Redmi Note 8 Pro Technical Specifications
- Display: 6.53-inch IPS LCD screen, Full HD+ (2340×1080 pixels), 19.5:9 aspect ratio, Corning Gorilla Glass 5 protection
- Rear Camera: Quad camera – (64 MP, f/1.8, Dual Pixel PDAF) + (8 MP, f/2.2 (wide-angle) + (2 MP, f/2.4, macro lens) + (2MP, f/2.4, portrait lens)
- Front Camera: 20 MP, f/2.2
- CPU: Helio G90T (2 x 2.27GHz Cortex A76 + 6 x 1.7GHz Cortex A55)
- GPU: Mali G76
- RAM: 6GB, 8 GB
- Storage: 64 GB, 128GB; Expandable
- OS & UI: Android 9.0 (Pie) with MIUI 10 on top
- Sensors: Fingerprint, Gyro, accelerometer, proximity, compass
- Battery: 4500 mAh; USB Type-C port
- Redmi Note 8 Pro Price in Nepal: Rs. 26,999 (6/64GB) | 29,999(6/128GB) | 32,999(8/128 GB)
2. Redmi Note 9 Pro
The Redmi Note 9 Pro has a lower starting price than its predecessors, but also doesn't offer all the modern features that you might expect. It has a 6.67-inch LCD screen with a 60Hz refresh rate and hole-punch front camera at the top. The processor is a Qualcomm Snapdragon 720G which is surprisingly powerful for this segment. You also get a 5020mAh battery and suppport for 18W fast charging.
The Redmi Note 9 Pro is powerful and everyday work will go smoothly. The display is large and crisp, making games and movies look good. You have a choice between variants, one with 4GB of RAM and 64GB of storage, and the other with 6GB of RAM and 128GB of storage.
The 48-megapixel primary camera was slightly disappointing overall, particularly in low light. There's also an 8-megapixel wide-angle camera, a 5-megapixel macro camera, and a 2-megapixel depth sensor. On the front you get a 16-megapixel selfie camera.
Redmi Note 9 Pro Specifications:
- Back Camera: 48MP f/1.8 Samsung GM2 sensor, 8MP f/2.2 ultrawide lens, 5MP f/2.4 macro sensor, 2MP f/2.4 depth sensor
- Front Camera: 16MP f/2.5 lens (1.0µm)
- Security: Fingerprint sensor (side-mounted), Face unlock
- Audio: 3.5mm headphone jack
- Connectivity: Wi-Fi 802.11 a/b/g/n/ac (2.4GHz + 5GHz), Bluetooth 5.0, GPS/GLONASS/GALILEO/BDS/NavIC, USB Type-C
- Battery: 5020mAh with 18W fast charging
- Display: 6.67-inch (2400 x 1080 pixels) Full HD+ IPS LCD panel
- Chipset: Qualcomm Snapdragon 720G; 8nm
- CPU: Octa-core (2×2.3 GHz Kryo 465 Gold & 6×1.8 GHz Kryo 465 Silver)
- GPU: Adreno 618
- RAM: 4/6GB LPDDR4x RAM
- Storage: 64/128GB UFS 2.1 (expandable)
- OS: Android 10 with MIUI 11 on top
- SIM: Dual SIM (Nano-SIM, dual stand-by)
- Redmi Note 9 Pro Price (6/128GB): Rs. 29,999
1. Samsung Galaxy M31
Samsung Galaxy M31 is definitely the best phones under Rs 30000 in Nepal. It retains the same Super AMOLED display, Exynos 9611 SoC and long-lasting 6,000mAh battery. The company has essentially upgraded the cameras to offer a higher resolution 64MP sensor and a quad camera setup.
Samsung Galaxy M31 Specifications:
- RAM: 6/8GB
- Storage: 128GB UFS 2.1 (expandable using SD card)
- Software & UI: Samsung’s One UI 2.0 on top of Android 10
Rear Camera: Quad-camera;
– 64MP, f/1.7 primary shooter
– 8MP, f/2.2 ultra-wide lens with 123º FOV
– 5MP, f/2.2 depth sensor
– 5MP, f/2.2 macro sensor
– Single LED flash
- Front Camera: 32MP, f/2.0 lens
- Security: Physical capacitative fingerprint scanner
- Audio: 3.5mm headphone jack, Dolby Atmos
- Connectivity: Dual-SIM (Nano), WiFi 802.11 a/b/g/n/ac, Bluetooth 5.0, GPS/AGPS/GLONASS/BDS, USB Type-C
- Battery: 6000 mAh with 15W fast charging
- Colors: Ocean Blue, Space Black, Red
- Body: 6.26 x 2.96 x 0.35 inches; 191 gm
- Display: 6.4-inches Super AMOLED panel
- Resolution: FHD+ (2340 x 1080 pixels); 19.5:9 aspect ratio
- Chipset: Exynos 9611; 10nm Mobile Platform
- CPU: Octa-core (4×2.3 GHz Cortex-A73 & 4×1.7 GHz Cortex-A53)
- GPU: Mali-G72 MP3
- Samsung Galaxy M31 Price in Nepal (6/128GB): Rs. 29,999
|S. No.||Best smartphones in Nepal under 30,000||Price|
|12||Nokia 7.2 (4/64GB)||Rs. 23,999|
|11||Honor 9X (6/128GB)||Rs. 29,999|
|10||OPPO F11 (4/128GB)||Rs. 29,990|
|9||Xiaomi Mi A3 (6/128GB)||Rs. 27,999|
|8||Vivo S1 (6/128GB)||Rs. 29,900|
|7||Redmi Note 7 Pro (6/128GB)||Rs. 25,999|
|6||Realme 5 Pro (4/128GB)||Rs. 26,990|
|5||Samsung Galaxy M40 (6/128GB)||Rs. 25,990|
|4||Samsung Galaxy M30s (6/128GB)||Rs. 28,699|
|3||Redmi Note 8 Pro (6/128GB)||Rs. 29,999|
Redmi Note 9 Pro
Samsung Galaxy M31