Non-BS6 diesel vehicles banned in Delhi as AQI nears 'severe plus'

A central panel ordered authorities to impose a ban on the operation of four-wheeled diesel light motor vehicles (LMVs) in Delhi and the surrounding NCR districts on Thursday as a result of Delhi's air quality indicator (AQI) degrading to barely a notch below the "severe plus" stage.

The Commission for Air Quality Management (CAQM) has exercised measures under Stage 4 of the Graded Response Action Plan (GRAP) with immediate effect, banning the use of diesel four-wheelers that are not BS-VI compliant as well as the entry of trucks into Delhi, as a result of Delhi's Air Quality Index (AQI) falling on Thursday to 450, which brings it just under the 'severe plus' category.

In Delhi, there are 3 lakh light motor vehicles that do not comply with BS-VI. The government established the BS, or Bharat Stage, emission regulations, as guidelines to control the emissions of air pollutants from equipment with internal combustion engines, such as cars. Prior to 2020, India followed the European (Euro) emission standards with a five-year lag, and in 2020, it skipped the transition to BS-V and went directly to BS-VI.

The order from the Commission for Air Quality Management (CAQM) states that the ban on diesel four-wheelers will be enforced in Delhi-NCR areas that border the city, and exempts BS-VI vehicles as well as those used for essential and emergency services. The state government may also soon decide whether to prohibit non-emergency commercial activity, close schools, and regulate automobile traffic on an odd-even basis.

According to a release from the CAQM, the measures were implemented “in the wake of unfavourable meteorological conditions anticipated to deteriorate the air quality of the NCR in the coming days” and forecasts suggest that Delhi's air quality is likely to remain in the "severe" or "severe plus" category between November 3 and 5.

This year, restrictions on polluting activities are being put in place three days in advance based on forecasts. In the past, the authorities would only put the measures into place once the PM2.5 and PM10 concentrations reached a certain threshold.