The recent data compiled by the pollution control board, showing consistently high pollutant levels in Gurgaon's air, serves as another reminder of just how grave a threat air pollution poses here.

Going strictly by the numbers, the daily average value of pollutants recorded for the month of April went well above the safety mark.

Among the most harmful of pollutants found in breathable air is what is called PM2.5 in technical terms. These particles of suspended particulate matter are tiny enough to find a passage straight to a person's lungs

. PM2.5 levels in Gurgaon in April went up to 127.5 micro grams per cubic metre (mgcm). The acceptable standard is no more than 60mgcm.

Along with this, nitrogen dioxide (NO2) and nitrogen oxide (NOx) peaked at over 184mgcm and 216mgcm respectively, which surpasses the average urban level of 80mgcm by a good margin.

What makes these numbers particularly alarming is the fact that they were not recorded in a dry month, when air pollution levels are expected to be high. The region witnessed several bouts of rainfall in April, and this means that the air was relatively cleaner, according to experts.

"April has been an exceptional month in this regard because of frequent rain here. Rain normally has a washout effect on pollution, but if despite that you are seeing high levels of pollutants in the air, it shows how bad things are," said Anumita Roychowdhury, executive director at the Centre for Science and Environment.

The main cause for this rapid rise in air pollution levels in Gurgaon, according to Roychowdhury, is vehicular emission. "First, the authorities here now need to bring out daily air pollution alerts, along with health advisories for people. And second, they will have to take immediate measures to reduce the number of vehicles on the roads by focussing on public transport and non-motorized travel," she said.