Lucy Cormack and Karuni Rompies – High-rise buildings in Jakarta will soon be forced to spray water mist from their rooftops as part of the government's desperate bid to tackle the toxic air pollution that has been choking the megacity for weeks.
It is the latest mitigation strategy in the Indonesian capital, which has a population of more than 10 million and is forever grappling with plummeting air quality.
Its pollution index was the world's worst in August, when fine particle matter ballooned to 19 times the level recommended by the World Health Organisation.
Four major factories have recently been ordered to shutter operations, while fuel-emitting industries have been threatened with sanctions if they fail to install mandatory mechanical scrubbers inside factory chimneys.
The smog is so thick that doctors have urged residents to wear masks and avoid walking outdoors, while the government has repeatedly called for civil servants to work from home to reduce the burden of dirty emissions from motorcycles and cars.
President Joko Widodo – said to be battling his own cough exacerbated by the conditions – has called for urgent intervention and enforcement of emissions restrictions.
He has urged locals to take public transport to cut down on the 996,000 vehicles entering Jakarta daily, and called for the widespread planting of trees.
He told an industry meeting recently that if they didn't install scrubbers they would face sanctions: "[I am] firm on this because the price for health we must pay is very expensive."
The president held cabinet talks on Monday to discuss air quality in Jakarta and its surrounds, receiving advice that increasing rates of respiratory infections and asthma were linked to air pollution.
Describing Widodo's persistent cough, Tourism Minister Sandiaga Uno last month linked it to poor air quality and said the president "has never felt like this".
The decision to introduce mist technology on 300 buildings comes amid a hurried effort to clear the skies before the city hosts the ASEAN Summit in September.
Head of the Jakarta Environment Agency Asep Kuswanto announced the policy after a mist system was installed at Central Jakarta's Pertamina Building. He said testing showed a reduction of harmful PM2.5 levels around the building.
PM2.5 particles have a diameter of 2.5 micrometres or less; about 3 per cent the width of a human hair. The fine particles – largely the product of smog from traffic, industry and fires – are small enough to penetrate the lungs and bloodstream and have been linked to an increased risk of cardiac arrest.
However, the jury is out on the efficacy of water mist for pollution mitigation.
"It's a water and energy-intensive approach that only works in the area being sprayed. The effect will also go away within a few hours of the sprays being stopped because of the particles still being emitted, and mixing from the other areas not being sprayed," said Duncan Watson-Parris, assistant professor at the University of California San Diego.
"I can sympathise with the desire for a quick fix, but this can only really be a stop-gap solution, as described above. Ultimately, we have to eliminate the primary source of the pollution: the burning of dirty fossil fuels."
Jakarta resident and business consultant Alexander Evan said he did not leave the house without a mask, which he changed regularly because "the dirty air sticks to the mask".
"There are also street kids selling cookies near Sarinah shopping mall in Central Jakarta. They don't wear masks, and I am sure they escaped the attention of the Jakarta government," the 48-year-old said.
"The real solution is decarbonisation... water mist is a temporary solution. It is not sustainable."
Retired civil servant Corina Manangka, 61, said she had been prescribed medication for a cough she recently developed. "I don't know if it is due to pollution or not, but the doctor told me to put on a mask when outdoors."
Street kiosks and fountains spraying fine mist were used across Europe during the northern hemisphere's recent heatwave to help cool residents and holidaymakers in places like Spain, Italy and Greece.
But using mist to target air pollution has more commonly been seen in China, which has used water cannons to reduce smog.
Mist has also been used in Delhi, one of the world's most polluted megacities, where average annual particle pollution can be more than 25 times the World Heath Organisation's guidelines.
India was among six countries in Asia and Africa named in a report this week for suffering the worst air pollution. The Air Quality Life Index study by the University of Chicago's Energy Policy Institute concluded that fine particle air pollution was causing the average person on the planet to lose 2.3 years of life expectancy.
"The impact of PM2.5 on global life expectancy is comparable to that of smoking, more than three times that of alcohol use and unsafe water, more than five times that of transport injuries like car crashes, and more than seven times that of HIV/AIDS," the report found.
In a separate effort to minimise pollution, Indonesia recently used weather modification technology, also known as "cloud-seeding", to induce rain.
The practice, conducted by Indonesia's National Research and Innovation Agency in late August, involves injecting clouds with substances to speed up rain production.
The Environment and Forestry Ministry said the weather modification had improved air quality in areas where rain fell, including in Bogor, a city south of Jakarta.
Cloud-seeding is widely used in the United Arab Emirates, which conducts an ambitious program throughout the year to force precipitation.