i live near Islamabad. I think lemon provides them with vit c which helps them in extream heat. Some other experience member may explain it how it works. You can give them some cold / frozen watermelon, mine love them. And one more thing you can do, take frozen water bottle (yoy can use 1.5 or 2.5 soft drink plastic bottle) freez them in refrigerator and put it in the cage or where ever they are kept. Them will sit on or beside it and it will help them