Reflective roofs combined with radiative cooling/night sky cooling is one of the most cost effective way to reduce heat indoors. Along with that, India needs to

Reflective roofs combined with radiative cooling/night sky cooling is one of the most cost effective way to reduce heat indoors. Along with that, India needs to start mandating energy efficiency standards for new construction. Insulation is extremely poor for most houses, leading to very energy intensive cooling requirements in the summer months. Ancient Indian architects already knew how to passively cool buildings - pools of water or stepwells at the base of the building (https://edition.cnn.com/2012/02/28/world/asia/ancient-air-conditioning-architecture/index.html https://edition.cnn.com/2012/02/28/world/asia/ancient-air-co...). It was used in Jaipur, Rajasthan but may not be that effective in humid Chennai, however.