On Day 4, Phase 2 of Delhi's Odd-Even there's some great and some not so great news. According to a survey by TERI there's been an improvement in air quality, but the bad news is that it's only marginal. Delhi air is still three times worse than what is considered safe! This can only mean one thing - the Odd-Even has its work cut out, because the detractors will not have the winters to blame for worsening air quality.

Did Odd-Even work the last time? TERI says no

“Over the weekend, the 24-hourly pollutant concentrations showed a dip. The PM2.5 (particles with diameter less than 2.5 micrometer) concentrations are 0.8-2.1 times the prescribed standards at various locations in NCR. PM10 levels which consist of particles from both natural and anthropogenic sources showed higher violation of 2.3-3.6 times of the standard. During the last week, the average ratio of PM2.5 to PM10 concentrations at different stations varied between 0.27 to 0.4, which depicts higher contributions from coarser particles from crustal sources. In winters, during the odd-even phase –I, this ratio was observed to be 0.52-0.63 which depicted higher contributions from combustion based sources in the season,” read the report by TERI on April 17th.

TERI data shows that some parts in Delhi showed substantial decline in PM2.5 on April 17th compared to days before the implementation of Odd-Even. For example on April 9th, the PM2.5 in Anand Vihar area was a whopping 280 ug/m3 (approx) whereas on April 17th it came down to 130 (approx). Similar declines were witnessed in other parts of the capital.

PM10, however, hasn’t seen the desired decline. Places like Anand Vihar where it was at peak on April 16th (400 approx) haven’t witnessed a big drop on April 17th. It was still at the 350 mark.

But despite some positive reports coming in, the pollution levels in Delhi are still at dangerous levels.