A Bengaluru neighbourhood's toxic air portends India's future

As a national debate grows over toxic air, some national-level solutions that appear expensive are far cheaper than the costs of doing nothing

On the day this story was written, April 10, 2015, the area with India’s most toxic air—among 10 cities where a new National Air Quality Index functions—was south Bangalore’s BTM Layout, a booming residential area dotted with restaurants and located conveniently near office towers and a web of highways. There wasn’t enough data to compute the index—calculated from six pollutants—but levels of a key pollutant, PM2.5, in BTM Layout touched 500 μg/m³, or 1200% more than levels considered safe for humans (μg refers to micrograms, or a ...