New Delhi: With air quality worsening in the national capital, Delhi Environment Manjinder Singh Sirsa has ordered 50 per cent of the workforce in his departments to work from home, official sources said on Friday.

Under Stage III of the Graded Response Action Plan (GRAP), invoked when the AQI falls in the "severe" category (401-450), the Commission for Air Quality Management (CAQM) has asked the Delhi government and other NCR state governments to decide on allowing public, municipal and private offices to operate at 50 per cent staff strength, with the rest working from home.

"Going by CAQM guidelines on air quality, heads of departments are free to take decisions regarding allowing work from home. Essential services will not be covered in this," a government official said.

Transport Minister Pankaj Singh has also directed his departments, including health and family welfare and information technology, to work from home.

Besides the environment, Sirsa holds the portfolios of food and civil supplies, industries and forest and wildlife.

The Union government may also permit work-from-home for its employees, according to the revised GRAP schedule.

Delhi's air quality remained toxic and in the "very poor" category on Friday, with the AQI settling at 373 at 4 pm as a thick smog blanketed the city's skies, reducing visibility and causing breathing difficulties for many.