Air pollution is a serious threat to the planet. The faster an economy grows, the more it pollutes the atmosphere. It's not just the cars and factories, the burning of solid fuels in developing countries also contributes to the problem. In fact, the way things are headed, everybody in big cities will be forced to wear gas masks in the near future. According to a recent survey by the World Health Organisation (WHO), 15 Indian cities feature in the top 30 most polluted cities in the world. In other words, half of the most polluted places on the planet are in India. This is a major cause for concern for everyone.

4. Patna

The capital of Bihar has several mills and factories that manufacture agricultural goods. These are believed to be the main reasons for the pollution here.

3. Kanpur

This town in Uttar Pradesh has factories producing textile, fertilizer, chemicals, two wheelers, soaps, and pan masala. Little wonder then that Kanpur is on this list!