Despite the Supreme Court order in this regard issued three weeks ago, the Central Pollution Control Board (CPCB) has failed to notify the “grade response plan” for different levels of pollution.

Meanwhile, according to the India Meteorological Department (IMD) officials, shallow fog is likely to occur in Delhi-NCR with mostly clear skies till December 23. In neighbouring east and west UP, moderate fog with isolated dense fog in many areas is expected to build up from December 22.

“There will be good sun and increased wind speed in the coming three days in Delhi. Dense fog is likely to return on Christmas eve (December 24). Also, minimum and maximum temperatures will dip further by 1 to 2 degrees around this time, which can affect air quality adversely,” said R Vishen, Scientist-In-Charge, Regional Meteorological Centre (RMC), IMD.

Environment experts said that the wind speed has increased from 1 km per hour last week to 10 km per hour, which will help pollutants in the air to disperse. If polluting activities and emissions are not controlled, however, it will keep the air quality in the same bracket.

“Delhi cannot depend on weather alone to do away with air pollution.There is no reason why the Centre should delay notifying the plan, which makes it legally binding on the states to follow it. There is an enormous volume of emissions from industrial units located in Ghaziabad etc, which have to be monitored in order to bring down the pollution levels in Delhi,” said VivekChattopadhaya, Senior Scientist, Centre for Science and Environment (CSE).

Under the plan, the air quality has been divided into four categories — moderate to poor, very poor, severe and emergency — and specific actions are to be taken for each situation.

The CPCB officials claimed that the plan to deal with different categories of pollution is already in the process of being notified. “We are in the process of putting the detailed plan across the states and government agencies within Delhi,” said a senior CPCB official.