Mumbai: As the Deonar dumping ground fire raged on, Mumbaikars for the second consecutive day woke up to a thick smog and high pollution levels.So high, in fact, that they matched those of Delhi and outstripped the worst seen last year during the Diwali season.Having recorded an Air Quality Index (AQI) of 325 in the morning, Mumbai saw an AQI of 341 on Friday evening, exact y what pollution-hit Delhi registered for the entire day , according to real-time data made available by the System of Air Quality and Weather Forecasting and Research (SAFAR). Experts attributed the pollution spike to weather conditions and an increase in PM 10 (particulate matter less than 10 micron in diameter), which could be due to the Deonar fire. Friday was thus the city's most polluted day since June 2015 (when SAFAR started recording data). The previous worst was an AQ of 313 on November 12, the day after Diwali.The year 2016 had also begun on a bad note as Mumbai had recorded an AQI of 300 on January 1.AQI levels higher than 200 are hazardous for health, and if they are between 300 and 400, they are considered very poor, with health experts advising people with heart or lung diseases, senior citizens and children to avoid exertion. AQI uses the 24-hour averages of pollutants, including sulphur dioxide, nitrogen oxide, carbon monoxide, ozone (O3) and particulate matter.“The weather and increased moisture are causing a spike in pollution levels, but the huge jump is because of the higher concentration of PM 10 pollutants. Open bio-fuel burning will enhance the coarser particles like PM 10 rather than PM 2.5.Areas like Chembur and Mazgaon are giving very high values and are probably affected by the dumping ground blaze,“ said Gufran Beig, project director, SAFAR.Humidity levels in the city were high on Friday morning, with Colaba recording relative humidity of 87% and Santacruz recording 92%.Most of the 10 suburbs in the city where SAFAR monitors air quality recorded, on Friday morning, AQI in the very poor category. Malad, with an AQI of 432, saw the worst of it, while Mazgaon with 211 was the best.Residents who live close to the dumping ground had a difficult time.“On Thursday , we didn't feel the smoke inside our house, but Friday was very bad and we felt choked. The visibility was very poor. My younger daughter has taken ill and is on the nebulizer. A friend who has undergone an eye surgery recently has been complaining of discomfort due to excessive watering of eyes,“ said Seema Balan, a resident.SAFAR, a system developed by the Indian Institute of Tropical Meteorology, Pune, along with partner institutions India Meteorological Department (IMD) and National Centre for Medium Range Weather Forecasting (NCMRWF), has forecast Mumbai's air quality to worsen on Saturday with a predicted AQI of 343.Activists said there is an urgent need to address the pollution problem. “We address such sources of pollution only as an emergency . We focus only on vehicular pollution as a source. We must tackle all sources like garbage dump, coal storage, and burning of plastic as a larger problem, otherwise we won't find the right solution,“ said Sumaira Abdulali, environmentalist and convener of Awaaz Foundation.