he Mumbai skyline, forming a backdrop to the ocean, is one of the city’s most iconic sights. But drive down Marine Drive or the Bandra-Worli sea link and you’re likely to see the skyscrapers only through a thick brown mist, particularly in the early morning or around sunset.
Mumbai has an annual tryst with smog or haze during the winter months, starting November. However, over the past couple of years, the haze seems to have set in as early as October, a phenomenon that could cause a variety of health problems for residents.
According to officials from the Indian Meteorological Department, haze-like conditions, though normally associated with winter have begun to appear in the months immediately following the monsoon. There are a variety of factors for this. “Post the monsoon, the winds that blow through the city are hotter and they bring a lot of dust, says IMD’s deputy director K.S. Hosalikar. “Another factor could be that during the monsoon, a lot of dust and other particles suspended in the atmosphere are washed down to the ground. After the monsoon, as the weather becomes dryer, these particles could float up in the air,” he explains.
While the problem has been gradually exacerbated by increasing population and hence more pollutants being released into the air, the situation is only likely to get worse with the onset of winter and a drop in the sea breeze. Sea breezes are stronger in summer than during winter because of the large temperature differences between land and ocean water at that time of the year. As the sea breeze drops in the months following November, it means that pollutants suspended in the air cannot be blown away as easily as they are in summer.
A senior met scientist said winter also sees an inversion of normal temperature patterns which leads to pollutants being trapped in the lower layers of the atmosphere. An official from the Maharashtra Pollution Control Board (MPCB) said anything above 100 micrograms of suspended particulate matter (SPM) in 1 cubic metre of air is bad for health.
The MPCB regularly generates air pollution data from its station in Bandra that shows a sharp rise in pollution levels post monsoon. Up to September end, AQI level was below 100 – indicating only minor breathing discomfort to sensitive people. By the start of October, the readings shot up over the 100 mark – indicating breathing discomfort to people with lung and heart disease, children and older adults. On certain days towards the end of the month and in the first and second weeks of November, it comes dangerously close to 200, a level which indicates breathing discomfort to all people on prolonged exposure.
Doctors say that the increased levels of pollution are most likely to affect children and patients with chronic lung diseases such as asthma. Along with the sudden chill in winter, the increase in pollutants means that over the last few years, the number of patients coming with breathlessness has increased,” says Ramesh Kulkarni, a GP practising in Thane.
