Why the leaves of eggplant are curling ?

No white flies right now. Proper treatment of white flies is being continued for last one month.

I noticed same problem with tomatoes . Since tomatoes and egg plants belong to same family , I think It might be a case of over watering or underwatering. Rarely it can be a virus also or fungi that causes plant to wilt . Just check your watering and soil moisture levels . Eggplant prefer light soils. Also curl upwards is a sign of temperature and humidity stress which is nothing to be worried about. I checked West Bengal weather.. checked temperature ND humidity . Temp is good but humidity is very high . Why don't you prune the grass and weeds around your eggplant . It might help reduce the local humidity around the egg plant . Hope my answer helped .

We had heavy rain a few days ago . But now the moisture level in the soil is more or less ok. But the humidity is quite high. The land was prunned a few days ago. There is not much grass right now. The curl may be due to stress condition. Thank you.

I think climate change and especially rising and falling temperatures could be the causes