I want to by a new smartphone which phone is best in price range below 20000?

Go for Sony Xperia C without a doubt. I'm using this phone from last month and it is awesome. Watching movies and playing games is great on its 5-inch qHD Display. Every game runs smoothly and it never heats. Battery life is much better than my old Galaxy s3. The best thing about the Xperia C is the user-experience. It is the best phone at this range. Go for it.

KEY FEATURES OF Sony Xperia C:-

1.2 GHz MTK6589 Quad Core Processor
Wi-Fi Enabled
8 MP Primary Camera
0.3 MP Secondary Camera
FM Radio
Dual SIM (GSM + GSM)
Expandable Storage Capacity of 32 GB
5-inch TFT Capacitive Touchscreen
Android v4.2.2 (Jelly Bean) OS

See reviews and buy it at Flipkart->http://www.flipkart.com/sony-xperia-c/p/itmduzj2bhajj6gz?pid=MOBDP6W6BJPDAHWG&srno=b_13&affid=svmtruegma

I think they are all below $20,000 so you shouldn't have a hard time finding one

Today we have for you the list of top 5 smartphones that offer maximum value for money in the price range of Rs 10,000-20,000.
1. Moto G (Rs 12,499/Rs 13,999)

4.5 inch display with a resolution of 1280 x 720 pixels and Gorilla Glass 3 on top of it
1.2 GHz quad core Snapdragon 400 processor
Adreno 305 GPU
Android 4.4 KitKat
1GB RAM
8GB/16GB of internal storage, non-expandable
5MP rear camera with LED flash and a 1.3MP front camera
3G, Wi-Fi 802.11 b/g/n, Bluetooth 4.0, microUSB 2.0 and GPS with GLONASS
2,070 mAh battery

2. Lenovo K900 (Rs 18,999)

5.5 inch display with a resolution of 1920 x 1080 pixels with Corning Gorilla Glass 2 on top of it
Android 4.2 Jelly Bean
2 GHz dual core Intel processor which is way more capable than the regular quad cores
PowerVR SGX544 GPU
2GB RAM
32GB internal storage, non expandable
13MP rear camera with LED flash and a 2MP front camera
3G, Wi-Fi 802.11 b/g/n, Bluetooth 4.0 and GPS
2,500 mAh battery

Blackberry Z10 (Rs 17,990)

4.2 inch display with a resolution of 1280 x 768 pixels
BB OS 10
1.5 GHz dual core Snapdragon S4 Pro processor
Adreno 225 GPU
2GB RAM
16GB internal storage, expandable by another 64GB
8MP rear camera with LED flash, 2MP front camera
4G LTE, 3G, Wi-Fi 802.11 b/g/n, Bluetooth 4.0, NFC and GPS
1,800 mAh battery