Kolkata’s Cooling Boom Masks A Hidden National Climate Crisis

In Kolkata, air-conditioning has quietly become a household staple. Analysis across seven cities in the iFOREST survey titled, Climate Cost Of Air-Conditioning: National-Level Survey on Residential AC Usage, Refrigerant Leakage and Climate Risks, shows that 83% of AC-owning households in Kolkata have just one unit, reflecting the national trend where multiple ownership remains rare.

While the city appears more efficiency-minded than others, 42 per cent of Kolkata’s units are five-star rated, compared to 28 per cent nationally, the environmental blind spots remain sharp. Nearly 69 per cent of households in the city are unaware of the climate impact of refrigerants, the highest level of unawareness among the seven metros surveyed.

On usage, Kolkata’s households run their machines for about four hours a day on average, slightly above the national mean of 3.9 hours. Refilling is also common, with 42 per cent of units in the city topped up annually, at an average cost of ₹1,600 per service. Each refill represents not just a recurring household expense but also a leak that has already taken place, sending potent greenhouse gases into the atmosphere.

Zooming out to the national level, the iFOREST study found that across Delhi, Mumbai, Kolkata, Chennai, Ahmedabad, Pune and Jaipur, 87 per cent of households now own at least one air-conditioner, while 13 per cent own more than one. India’s residential stock already stands at around 76 million units, a figure projected to triple to 245 million by 2035.

Nearly 80 per cent of these machines are less than five years old, with over 40 per cent bought in just the last two years. Most carry a three-star label, showing that while families are somewhat conscious of energy efficiency, cost remains the primary driver.

Outlook reached out to AR Ravishankara, a scientist and professor of chemistry and atmospheric sciences at Colorado State University, Fort Collins, to talk about Hydrofluorocarbons (HFCs) that are presently used in the ACs.

Professor Ravishankara said, “Just to go back into history, the first, these chemicals called ozone-depleting substances, CFCs, were used as refrigerants... Then what came about is something called these HFCs. HFCs do not contain any chlorine or bromine, so they do not contribute to ozone layer depletion. Some of them are also very important greenhouse gases, just like CO₂. But if CFCs had been continually used, and if there were no Montreal Protocol, by now CFCs would have been more important than CO₂ for the climate process. But that was avoided because of the Montreal Protocol.”

But the core of the crisis lies in the issue of refrigerant leakage. In principle, an air-conditioner should run for at least five years without requiring a refill. Yet in practice, 40 per cent of India’s national stock is refilled every single year. Among older machines, the figure is far worse, 80 per cent require an annual refill.

Even relatively new machines, less than five years old, are subject to unnecessary top-ups in nearly a third of cases. Each refill signals that the gas has already escaped into the atmosphere, fuelling both climate change and household expenses.

The scale of this leakage is immense. In 2024 alone, Indian households consumed 32,000 tonnes of refrigerant gas for servicing, a quantity that translated into 52 million tonnes of carbon dioxide equivalent emissions.

Financially, the losses are just as stark. With an average refill costing around ₹2,200 per unit, families spent ₹7,000 crore in 2024 alone on an exercise that should not have been needed. Unless practices change, that figure could climb almost fourfold to nearly ₹27,540 crore by 2035.

Professor Ravishankara further added, “If they keep recharging the air conditioning units, that means there's more and more use of these chemicals, which are going to end up in the atmosphere. I am from Banagalore and I have watched that with my own eyes that people were flushing the air conditioning unit of a car and just letting it go into the air… Enforcement and compliance are very big issues to minimise emissions of these compounds. HFC-134A, for example, if you emit one kilogram of that compound, it is equivalent to emitting roughly 1,500 kilograms of CO₂. Some of them are also very important greenhouse gases, just like CO₂.”

As Sanjeev K. Kanchan, one of the report’s co-authors, also underlines the magnitude of the problem by pointing to the warming potential of refrigerants, “One commonly used refrigerant, R-410A, has a warming potential 2,088 times higher than CO₂. Another, R-22, is around 1,600 to 1,700 times higher. The newer R-32, now common in the market, is still 675 times higher. These numbers show how large the impact is when leaks are left unchecked.”

Taken together, the combined impact of refrigerant leakage and electricity consumption from India’s AC stock has already reached between 156 and 161 million tonnes of CO₂ equivalent in the mid-2020s, a figure comparable to the annual emissions of all passenger cars in the country. If left unchecked, residential ACs could emit 329 million tonnes of CO₂ equivalent by 2035.

The environmental risks go beyond climate change. While older ozone-depleting substances like CFCs and HCFCs have been phased out under the Montreal Protocol, their replacements, HFCs, are now fuelling a different crisis.

India ratified the Kigali Amendment in 2023, committing to phasing down HFC use, but weak enforcement means current practices continue largely unchecked.

The India Cooling Action Plan (ICAP), released in 2019, laid out an ambitious roadmap to cut overall cooling demand by up to 25 per cent and refrigerant demand by nearly 30 per cent by 2037–38, while doubling appliance efficiency and expanding technician training.

Yet progress has been slow, with little improvement in regulating refrigerant handling during servicing, which remains the biggest source of leakage.

Recent amendments to e-waste regulations in 2023 require refrigerant recovery and destruction at approved facilities, but these rules apply mainly to end-of-life units. Everyday use and routine servicing, where most leaks occur, remain largely outside the regulatory net.

In contrast, countries such as Norway and Australia enforce strict technician certification and penalise improper handling. In India, by contrast, virtually anyone can dismantle and refill an AC unit without formal training or accountability.

Professor Ravishankara also said that it would be very helpful if India were to establish dedicated ways and locations to measure these chemicals in the atmosphere, so one could find out much more accurately how much is actually being released.

“I’m very heavily involved in efforts to measure these compounds across the globe, and such measurements in India would be extremely valuable. The country has an extremely competent workforce of scientists and enormous technical capabilities to carry out this work; it just needs to make it a priority”, says Professor Ravishankara.

Awareness among consumers is equally limited. While many pay attention to star ratings and thermostat settings as ways to reduce electricity bills, nearly half of those surveyed said they were unaware of the climate impact of refrigerants. Cost was also a decisive barrier, only about a third of households said they were willing to switch to alternatives even if they understood the environmental consequences.

Kanchan stressed the gap, “People are already careful about buying three-star or five-star ACs and setting their thermostats around 22 or 23 degrees; not because they are environmentally conscious, but because electricity is expensive. But 43 per cent of households we surveyed were not aware that refrigerants have a huge environmental impact. They had no climate consciousness. That shows how much work still needs to be done.”

The iFOREST report recommends a comprehensive refrigerant management law covering the full lifecycle of AC gases, mandatory technician certification, manufacturer responsibility for recovery, and stronger consumer awareness. Implementing these measures could prevent hundreds of millions of tonnes of CO₂ equivalent emissions and save households billions in unnecessary refills by 2035.

Regulation, Kanchan argues, cannot realistically limit household ownership but must instead target servicing practices where the bulk of emissions and expenses originate. Upon being asked if limits could be placed on how many units a household may own, he says, “It is a little difficult administratively and from a regulatory perspective to put such limits. You cannot directly control what people can afford, but you can indirectly control it through higher taxes or conditions on buying. Like with electric vehicles, where the government offers discounts and exchanges, similar incentives or restrictions can be designed for ACs. The challenge is that a car runs in a public space, so regulation is easier. An AC is inside the home; once you buy it and pay GST, nobody cares after that. That is why regulation has to focus on servicing and refilling, because that’s where problems arise.”

For him, the urgency of action cannot be overstated. “The masses don’t fully understand how urgent this is,” Kanchan admitted. “But when you explain that it directly affects their pocket as well as the climate, people begin to listen. That’s where awareness and enforcement need to meet.”

The paradox is stark: the very machines purchased to shield households from punishing heatwaves are at the same time helping to intensify them.

But as the cities expand and summers grow ever more dangerous, the demand for cooling will only keep rising. But we are aware that the consequences of climate change are already becoming severe and life-threatening with each passing year, wherein one needs to be reminded that there is no Planet B.