Chandni Chowk and ITO intersection have air pollutants higher than standards. Replying to supplimentaries in Rajya Sabha, Minister of State for Forest and Environment Namo Narain Meena said on Friday that levels of nitrogen dioxide were observed to be within the ambient air quality standards at all monitoring stations except ITO and Town Hall (Chandni Chowk).

The higher concentration of nitrogen dioxide at ITO and Chandni Chowk could be attributed to high traffic density at the monitoring points, the Minister said.

Ambient air quality monitoring is carried out at Siri Fort, ITO, Delhi College of Engineering, Town Hall (Chandni Chowk), Mayapuri Industrial Area and Sarojini Nagar.

"The levels of Respirable Suspended Particulate Matter (RSPM) are observed to be generally exceeding the national ambient air quality standards at all locations," Meena said.

The main sources of air pollution in Delhi, he said, were vehicular exhaust emissions, industrial activities including power plants, re-suspension of dust, operations of diesel generator sets and burning of fuel for domestic purposes.

"A study has been initiated for Delhi to ascertain contributions to RSPM from various sources," he said.

here are many steps that have been taken to control air pollution. Some of these include enforcement of stricter auto exhaust standards for new vehicles at the manufacturing stage, use of improved fuel quality, stringent diesel generator set emission norms, promoting gas based power plants and cleaner technologies.

"With several steps taken, there are visible positive effects in the ambient air quality, particularly, in terms of reduction in the levels of sulphur dioxide," Meena said.

He, however, said at present, there were no conclusive reports indicating that a large number of people were suffering any kind of respiratory diseases due to air pollution in Delhi.