Which substances are polluting air the most? What is the ozone hole? How much CO2 is emitted by burning 1 litre of petrol? Which country emits the maximum CO2 per person? What is BS-IV? How are climate change and air pollution related? What is the Kyoto Protocol? Which are the most and least polluted cities of India? Know the answers to these, and 42 more frequently asked questions, on air pollution, its various aspects, and impacts.