Environment Minister Jayanthi Natarajan also informed the Rajya Sabha that the Central Pollution Control Board (CPCB) is monitoring air quality in Delhi and steps have been taken to control environmental pollution.
Noting that health effects, such as manifestation of respiratory ailments, could be associated with pollution, she said, "Due to various confounding factors, no conclusive data established co-relation between pollution and consequential health impacts."
In a written reply, she said the data from 2001 to 2011 indicate that the SO2 levels were within prescribed National Ambient Air Quality Standards.
"However, the levels of NO2 and PM10 exceeded prescribed standards," she said.
Steps taken by the Government to control environmental pollution include formulation of a comprehensive policy for abatement of pollution, supply of improved auto-fuel and tightening of vehicular and industrial emission norms, she said.