Every winter, as inversion leads to smog-filled days and nights across entire north India, the western region of the country -- by contrast -- looks much cleaner. A new analysis of regional air pollution levels, done by the Centre for Science and Environment, says air pollution is rapidly becoming a matter of concern in the western states of Maharashtra and Gujarat as well. To get full access to this story, "Subscribe Now", in just Re.1 for the next 24 hours...