The Delhi High Court on Friday directed the Centre to file a detailed response to a petition seeking lowering of goods and services tax on air purifiers in view of worsening air quality in the national capital.

A vacation bench of Justices Vikas Mahajan and Vinod Kumar granted 10 days' time to the central government to file its reply to the petition and listed the matter for further hearing on January 9.

The court was informed by the Centre's counsel that the meeting of GST Council has to take place physically only and it is not possible to convene the meeting through video conferencing.

Additional Solicitor General N Venkataraman, representing the Centre, sought time to file a detailed reply.

Venkataraman, representing the Centre, added that if the GST Council mechanism is bypassed in this case, it could open a Pandora's Box whereby more GST exemptions may be sought without following the proper procedure.

"This will open a Pandora's Box. Parliamentary committee has recommended something to us. It will be considered. There is a process. We are not saying anything. We are not saying whether it will be done or not. Constitution issue is involved," Live Law quoted the ASG Venkataraman as saying.

The ASG went on to assure the court that the government will inform by its counter-affidavit as to when a GST Council meeting can be scheduled.

"The issue is such that everybody is concerned," the court then remarked.

The court was hearing a public interest litigation (PIL) seeking directions to the central government to classify air purifiers as "medical devices" and reduce the goods and services tax (GST) to the five per cent slab. Air purifiers are currently taxed at 18 per cent.

The petition by advocate Kapil Madan said that purifiers cannot be treated as luxury items in view of the "extreme emergency crisis" caused by severe air pollution in Delhi.

The high court maintained that something should be done to bring down the cost of air purifiers in Delhi, given the air pollution crisis that has hit the national capital.

"The Court's concern was given the situation in Delhi and the surrounding areas. Why can't it be done? Do whatever you have to do. Right now, an air purifier costs 10-15K. Why not bring down the GST to a reasonable level where even a common man can afford an air purifier?" Live Law quoted the bench as saying.

On December 24, the court had directed the GST Council to meet at the earliest and consider lowering or abolishing GST on air purifiers.

The matter was listed today to inform the court as to when the Council can meet and whether it was possible for the Council to meet virtually, if not physically.

The air quality in the city slipped into the 'very poor' category on Friday after witnessing marginal improvement for two days.

The overall Air Quality Index (AQI) stood at 310. The air quality was recorded as 'moderate' at Lodhi road station with an AQI of 185, while it was 'very poor' in at least 24 stations.

Delhi recorded 'poor' air quality in the last two day.

According to the Air Quality Early Warning System (AQEWS), the air quality is likely be in the 'very poor' category for the next six days.

The current average wind speed, which is less than 10 kmph, is unfavourable for dispersion of pollutants, the India Meteorological Department (IMD) said.

According to the Central Pollution Control Board, an AQI between 0 and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor', and 401 to 500 'severe'.

According to the IMD, the maximum and minimum temperatures in Delhi on Friday are likely to be in the ranges of 21 degrees Celsius to 23 degrees Celsius and 6 degrees Celsius to 8 degrees Celsius respectively