Which is India’s noisiest city?

New Delhi: The red light at a traffic junction is the universal sign for vehicles to stop — but in India, it is also a signal to start something else: relentless honking. To address this menace and punish impatient drivers, the Mumbai Police have launched a novel ‘Honk More, Wait More’ scheme. Now, if impatient drivers honk at signals, they are simply increasing their wait time.

This may seem a quirky solution but it addresses a serious problem. When noise from constant honking is added to the general cacophony in cities, it becomes noise pollution — and this pollution can be costly and dangerous too.

Because of the threats of noise pollution, the Central Pollution Control Board (CPCB) tracks noise-levels through monitoring stations spread across India’s major cities. In 2018 (the latest year for which data was available), Chennai was the noisiest among India’s six metros. Across the city’s 10 stations, the average noise levels during the day was 67.8 decibels (dB), much higher than the equivalent figure for Delhi (61). Since decibels are measured on a logarithmic scale, a 10 dB increase actually translates to a doubling in perceived loudness making differences between cities more significant.

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Almost every part of India’s cities, though, including Delhi, violates noise pollution standards. The government mandates that noise levels in residential areas should not exceed 55 dB during the day (and 45 at night).

In the 13 monitoring stations in residential areas across the six cities, this limit was violated during both day and night throughout 2018. Even designated silence zones, areas around hospitals, for instance, do not meet noise pollution standards. The area around ASHP Hospital in Mumbai is the quietest among the metros (54 dB) but still noisier than the limit (50 dB). Unsurprisingly, the noisiest parts of the city are in commercial and industrial areas. The area around Paradise junction in Hyderabad, a major commercial hub and a traffic chokepoint, is India’s loudest (79 dB).

All this noise can inflict significant damage. For a start, constant exposure to loud noise, such as regular honking hurts hearing, with children and the elderly especially vulnerable. According to data from the World Health Organization (WHO), South Asia already has the highest prevalence of hearing loss in the world among children and the elderly.

But noise pollution can also lead to deeper damage. It affects sleep, increases stress and even impairs cognitive development among children. According to a 2011 WHO study, noise pollution in Western Europe was found to be associated with greater risk of heart diseases, more stress-related mental health risks and slower child cognitive development.

Beyond the public health costs, noise pollution can even hurt the economy. Noise at night affects the quality of sleep which is considered an important determinant of well-being and productivity. Even during the day, working in a noisy environment hurts productivity.

An experiment in Kenya found that a 10 dB increase in noise reduces productivity by around 5%.

Eliminating noise from cities is impossible but measures, such as the Mumbai police’s traffic light initiative, can be an important first step in bringing noise pollution under control, according to Sumaira Abdulai, convenor at Awaaz Foundation, an NGO working on noise pollution.

“It is the right move because it will raise awareness. But there also has to be enforcement like there is for other issues like drinking and driving, and wearing seat belts. There has to be fines and penalties for honking unnecessarily. Only initiatives like these can prove to be a solution for noise pollution in the long run,” she said.