What are the challenges of growing Venus Flytrap in India where temperature is generally above 20 degree Celsius and reaches up to 44 degree Celsius for 2-3 months a year?
Can I grow those plants indoor during this season?
Also can I use wheat grass or dry sugar cane leaves to grow them if I don't get specific moss?
Venus' flytraps need a dormant period for 3-4 months during the year. During this period they need cooler temperatures and less water. There are various different methods that you can research, but one that might be best for India where it's warm almost all year is the following: take the VFTs out of the planting medium with the roots; rinse with distilled, rain, or reverse osmosis water; cut off the traps (they won't need them); put it in a plastic bag with a few drops of water; and store in a refrigerator.
I live in the US, but I've never heard of VFTs not being able to handle a lot of heat during the summer. All I've ever heard is that they need as much sun as possible, so they should be good in Indian heat.
In regards to the planting medium, 100% long fiber sphagnum moss or 1:1 sphagnum peat moss to pure perlite is recommended. These are recommended because they're slightly acidic and they have little to no nutrients in them. Carnivorous plants all get their nutrients mainly from bugs, and their roots will burn if they're put in nutrient-rich soil or fertilizer is added. I would guess that wheat grass or dry sugar cane leaves are not acceptable for carnivorous plants.