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Why the choices Delhi makes are a cruel joke in this baking heat

Who could have thought seasoned Delhi residents would give in to seasonal vagaries? But if it had a heat threshold, the national capital seems to have crossed it in the last one month.

delhi Updated: May 26, 2016 19:24 IST
Shivani Singh
Shivani Singh
Hindustan Times
Delhiites on a hot day last month. This April was the hottest ever globally, according to NASA.(HT file photo)

Who could have thought seasoned Delhi residents would give in to seasonal vagaries? But if it had a heat threshold, the national capital seems to have crossed it in the last one month.

The Met department sounded a red alert for Delhi and its suburbs where the temperature crossed 46 degrees Celsius. But then, analysed NASA, last month was the hottest April on record globally. In Delhi, an average temperature of 30.7 degree Celsius made it the seventh hottest April in 85 years. The Met department blamed the lack of rain.

No wonder that mercury trends are dominating the conversations. Smartphone weather apps have become popular. Travel schedules have changed. Socialising has reduced. Roads are less crowded. Delhi’s power demand is at an all-time high and the overworked distribution network is giving way leading to power cuts.

But Delhi has always been known for its extreme weather. “Dhoop mein aadhi raat ka sannata rahta tha” (sunny afternoons were as silent as midnight) is how poet Gulzar describes the harsh Delhi summer of his childhood. The hot, dry wind blowing from the Thar Desert in the west, colloquially called loo, is very much part of the Delhi legend. It ripened and sweetened seasonal fruits such as water and musk melon, our childhood staple to beat the heat, till artificial colours and sweeteners took over.

In pre-24x7 TV days, when daily weather was not a matter of ‘breaking news’, the summer was far more tolerable in Delhi, vouch many old-timers, even though the temperature often touched 45 degrees. There is a reason why Delhi feels so much hotter now. It’s called urban heat islanding that makes some pockets feel 3-4 degrees hotter than what it actually is.

A 2012 study by Centre for Atmospheric Sciences, IIT-Delhi, found that since 1990, there was a consistent increase in the night temperatures in the city, and not so much in the day temperatures, leading to an overall warming. Concrete structures such as roads, pavements, rooftops absorbed heat during the day and passed on the heat, forming a dome of warm air over surrounding areas. This heat would not get released after sundown, keeping night-time temperatures also high.

The study also found that between 1968 and 1985, Safdarjung in Central-South Delhi had higher night-time temperatures because it was more built up than Palam. But after 2000, when Palam saw excessive urbanisation, the two stations had almost the same annual mean minimum temperatures. Today, Palam is 2-3 degrees hotter than the rest of the city.

At 98%, Delhi has the highest level of urbanisation in India. In an attempt to build more and build fast, we have compromised on building designs and quality. Neighbourhoods have now become dense with multi-storey “builder” flats, with low-ceiling, thinner walls and hardly any ventilation. It is not surprising that many Delhi homes are dank and cold in winters and furnace-like in summers.

Outside, every bit of land is sealed in concrete. The trees are choking because their roots can’t breathe. Newly developed areas hardly have any large trees. The US department of agriculture says that the cooling effect of a healthy tree is equivalent to ten standard domestic air-conditioners operating 20 hours a day. According to NASA, when the suburban development in Atlanta, known as a city in a forest, ate up 380,000 acres of trees between 1973 and 1992, temperatures climbed 5-8 degrees Fahrenheit compared to the surrounding countryside.

Singapore has planted leafy trees along the city roads to cover entire stretches with canopy cover. Rooftop gardens, sky terraces and high-rise farming is picking up in public housing. While the earlier apartment blocks in its public housing didn’t have balconies, all new flats come with one and residents are encouraged to put green planters, even on the higher floors.

Changwon in South Korea is subsidising cool roofs — a technology of heat-reflective surfaces it picked up from Tokyo. It reduces the need for air conditioning, saves power and cuts carbon emission.

In Delhi, our solution has been to set new records in concretisation, consumption and pollution, and also the sale of air-conditioners every summer. That’s by far the cruelest joke this cruel season.

First Published: May 23, 2016 11:13 IST