"As per the Report of IIT Kanpur, the back trajectory analyses suggest that the crop residue burning and other biomass emissions may be transported to the capital from the sources upwind of Delhi," environment minister Anil Madhav Dave told the Lok Sabha in a written reply.

Dave also told the house that to curb pollution in Delhi, burning of paddy stubble has been banned in its neighbouring states like Punjab, Haryana, UP and Rajasthan.

He said that the high court has assigned the responsibility of prevention of stubble burning and biomass on the chief secretaries of the state governments, which have initiated steps for compliance.

"Available satellite images indicate that the enforcement of ban on paddy stubble burning in farmlands of Punjab, Haryana and parts of Uttar Pradesh has not been fully implemented and there has been significant level of stubble burning.

"Government has been monitoring various preventive measures to curb the burning of crop residue and check the pollution level in Delhi and NCR at regular intervals," Dave said.