Which Computer Case "Cabinet" do you own? Which Power Supply do you own. Make and Model would be helpful.
I suggest either a low cost Intel Pentium such as the Intel Pentium G4400, or an AMD APU such as the AMD A6-7470K 3.7GHz Dual-Core Processor.
I suggested Linux Mint 18.1 for the OS, you can use any OS you want. Later on add a NVidia GTX 1050 or AMD equivalent when you have another ₹6800 saved up.
I suggest reusing your Computer Case "Cabinet", 500GB Hard Drive and your DVD/RW.
The Intel CPU is going to give you the best results, but its a little over your budget.
INTEL BUILD
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Pentium G4560 3.5GHz Dual-Core Processor (₹5450.00 @ Amazon India)
Motherboard: Gigabyte GA-B250M-D3H Micro ATX LGA1151 Motherboard (₹5720.48 @ Amazon India)
Memory: Crucial Ballistix Sport LT 8GB (2 x 4GB) DDR4-2400 Memory (₹4037.79 @ Amazon India)
Power Supply: Antec 450W ATX Power Supply (₹5856.00 @ Amazon India)
Other: Linux Mint 18.1 - Serena (₹0.00)
Total: ₹21064.27
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-09 23:40 IST+0530
AMD BUILD
PCPartPicker part list /
Price breakdown by merchant
CPU: AMD A6-7470K 3.7GHz Dual-Core Processor (₹3375.00 @ Amazon India)
Motherboard: ASRock A88M-G/3.1 Micro ATX FM2+ Motherboard (₹4710.87 @ Amazon India)
Memory: Kingston HyperX Fury White 8GB (2 x 4GB) DDR3-1866 Memory (₹4037.79 @ Amazon India)
Power Supply: Antec 450W ATX Power Supply (₹5856.00 @ Amazon India)
Other: Linux Mint 18.1 - Serena (₹0.00)
Total: ₹17979.66
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-04-09 23:37 IST+0530