Freak haze, humidity choke city

Mumbai: Surprised by the winter-like haze blurring the trees in the park during your morning walk and finding it difficult to reconcile it with the daytime temperature hitting mid-30 degrees Celsius? A freak weather condition has hung the haze over the city for almost a week now.      Unseasonal rains in October and a spike in humidity levels have triggered the haze. Though humidity has dropped considerably over the past two days, the smog, bolstered by pollution, still sits over parts of the city, leading to a spike in allergic and viral infection cases, said officials.      Doctors say children and those already suffering from chronic respiratory problems such as asthma or bronchitis are more at risk. Pollution levels spike in city as rains recede and smog lingers Haze Is Usually Seen In Nov: IMD      The smog that has enveloped the city for the last week is unusual, say Met officials. "We generally see this kind of a weather situation in November. This time, however, the haze seems to have set in early," said K S Hosalikar, deputy director general of IMD, Mumbai.      The haze initially built up as humidity levels of about 60-65% coupled with cloud formation. Now, industrial and vehicular pollution have led to the smog lingering in the atmosphere, said officials from the meteorological department.      "There was moisture in the air which caused a haze. If the winds were stronger, it would have dispersed. But mild winds let it hang for many days," said an official from the India Meteorological Department (IMD).      As the rains petered out, the pollution levels have been increasing. Mumbaikars have been breathing in more than double the nitrogen oxide  levels. What's more, the suspended particulate matter too has been greatly fluctuating.      "Anything above 100 micrograms of suspended particulate matter (SPM) in 1 cubic metre of air is bad for health," said an official from the Maharashtra Pollution Control Board, adding that the levels are always higher in parts of the city. In Sion, for instance, the nitrogen oxide levels have been constantly above 160 units since last week. The SPM levels have been fluctuating anywhere between 60 and 261 units.      "Whenever the wind speed is low, the pollutants cannot be blown away. When the weather gets cooler in the next few days, the SPM levels are only likely to increase further," explained Dr Rakesh Kumar of the National Environment Engineering Research Institute (NEERI).      Officials said visibility in the morning (between 6.30am to 10am) has been around 1,500 metres instead of 2,000m. After sunset, the visibility has been around 3,000m instead of the usual 4,000-5,000m. "Visibility improves during the day. The pattern is likely to continue for the next two months as the onset of winter would again cause a haze," another IMD official told TOI.      "Right now, humidity is around 30% and moisture content low. Hence, the haze has lifted. Due to cyclone Phailin, there is a low pressure zone around Konkan which is causing mild clouds and smog around Marathwada," said Manoj Indulkar, scientific assistant at IMD, addfing that it will turn into fog as winter approaches.  MILD WINDS HELPING HAZE  WHAT'S CAUSING THE HAZE?  Moisture due to rain and cloud formation and a rise in humidity levels cause a haze. Industrial and vehicular pollutants add to it. If the wind conditions stay mild, the haze hangs for longer and doesn't disperse  THOSE AT RISK City doctors say children and those already suffering from chronic respiratory problems such as asthma and bronchitis are the most vulnerable Clouds and haze hang over highrises