The Centre has asked all metro rail corporations to install retrofitted devices in diesel generators being used by them, a move aimed at reducingparticulate matter emissions from DG sets.
In a letter to the corporations, the union housing and urban affairs (HUA) ministry said that according to National Clean Air Programme (NCAP), DG sets contribute 7-18 per cent to the ambient air pollution in non-attainment cities.
Non-attainment cities are areas with air quality worse than the National Ambient Air Quality (NAAQ) Standards.
There are several metro rail corporations, including Delhi Metro, Chennai Metro and Bengaluru Metro