LUCKNOW: Since 2011, at least 94 Indian cities have not met national air quality standards . Many of these cities have been on the list from 1990s, say CPCB officials.Neither the Centre nor the states have put in place a plan to ensure that cities get taken off this list. For the past couple of years when air pollution in Delhi, Kanpur, Lucknow and Varanasi touched dangerous levels, the CPCB did nothing to ensure that its directions on meeting air quality standards were enforced. Lucknowites had a feel of Delhi on Sunday as a sheet of dense smog enveloped the city and air pollution levels rose alarmingly-three to four times of the pollution witnessed on normal days and six to eight times of the permissible limits. The smog, which created a scare among people, is likely to remain till Tuesday .State Met director JP Gupta said the smog was formed by accumulation of pollutants in the air during this part of the year when temperatures are below normal, wind speed is low and moisture content is high. “The moisture content is high because easterly winds are dominating the atmosphere. The pollutants combine with tiny water droplets to form smog,“ he said. In dry weather, pollutants settle down or are blown away.The easterly winds had also led to clouding on Saturday, which caused drop in maximum and minimum temperatures. People woke up to haze on Sunday and as the day passed, the smog got thicker with addition of pollutants.Monitoring by the Indian Institute of Toxicology and Research (IITR) showed that PM2.5 and PM10 concentration in the air was around 400 micrograms and 800 micrograms respectively between 11am and 3pm, almost on a par with the pollution that made the city gasp on Diwali day.In comparison, Delhi on Sunday recorded PM2.5 and PM10 concentrations around 672 and 864 respectively.The permissible limits as per the National Ambient Air Quality Standard (NAAQS) for PM2.5 and and PM10 are 60 and 100 micrograms respectively . On normal days, PM2.5 and PM10 concentration in Lucknow is around 110 and 216 micrograms respectively .PM are fine particulate matter suspended in the air.They are hazardous for health and also reduce visibility in the air.“Not only the concentration of PM10 and PM2.5 was high, level of the extremely fine particulate matter PM1 (of diameter less than 1 micron) was recorded to be 145 micrograms per cubic metre of air,“ said IITR senior scientist S C Barman.