India, Oct. 21 -- As the air quality in Delhi slipped into the "poor" category on Wednesday, the Commission of Air Quality Management (CQAM) enforced stage-I restrictions of the Graded Response Action Plan or GRAP.

"The Air Quality lndex (AQI) of Delhi which was observed 179 (Moderate category)on October 20, has exhibited a sharp rise with AQI of 244 at 2 pm on October 21 (Poor category)," said the CAQM in a statement, news agency PTI reported.

GRAP is a set of emergency measures that kick in to prevent further deterioration of air quality once it reaches a certain threshold. The first stage, GRAP-1, kicks in when the AQI is between 201 and 300.

Under GRAP-1, restrictions are aimed at cutting pollution at source, such as restricting th...