The city was exposed to high-risk level
(UV) radiation on 23 days (37.7%) in April-May, compared to 18 days (nearly 30%) in Mumbai and 19 in Delhi, according to an analysis by Indian Institute of Tropical Meteorology (IITM), Pune, and System of Air Quality Weather Forecasting and Research (SAFAR).
The city’s UV Index touched medium-risk level on 38 days. Mumbai had one extreme risk day during the period.
The index, developed on the guidelines set by the
World Health Organization
, measures UV radiation on a scale of 1-10, with 1-4 posing no risk to people and 7-10 high risk when it’s advisable for all people to avoid direct sun exposure. When the index crosses 10—like it did once this summer—health experts say people should avoid even indirect sun exposure.
The city’s UV Index was never in the low-risk category, while Mumbai had two such days. The maximum risk of UV radiations is noon and 3pm, with its peak at 1pm. SAFAR monitors the UV Index in the city as well as in Mumbai and Delhi.
Gufran Beig, project director, SAFAR, “We cannot control the UV Index or exposure in the short-term, but we can take preventive measures like using sun protective clothing and sun blocks and avoid exposing ourselves to the direct sun for too long. Hence, it is critical to understand the ills of a high UV index. In the long run, steps must be taken to reduce the ozone layer depletion.”
Exposure to UV radiation poses the risk of cataracts, premature skin ageing, and skin cancer in the long run. While the health effects are worrisome, doctors feel Indians have a good
content protecting them from harm.
“The significance of UV Index to Indians is not the same as it is to Caucasians because we have a good melanin content which protests us well. While a high UV index could stimulate pigmentation, cause tanning or burning to a certain subsection of Indians who are extremely fair, it is not likely to affect our
. We have fewer instances of skin cancers as compared to the Caucasians. We must definitely protect our eyes using dark glasses because more UV radiations could mean earlier cataract,” said Nina Madnani, consulting dermatologist, PD Hinduja Hospital. And sensitive people must take extra care.
“Those with low pigmentation, sun sensitive disorders could see their conditions aggravate or might be at a risk when UV index is high,” she added.
Explaining reasons for Mumbai’s exposure to UV radiation, Baig said, “Mumbai is more vulnerable due to its geography. Proximity to waterbodies or sand restrict the solar radiation from getting absorbed.” As per SAFAR, the amount of UV radiation reaching the surface is primarily related to the elevation of the sun in the sky, the amount of ozone in the stratosphere, and the amount of cloud cover. However, thick cloud can greatly reduce UV levels and, surprisingly, certain types of thin cloud can magnify the UV radiation strength.