As a child, Kavickumar Muruganathan thought the hazy skies that descended upon Singapore every year were a distant problem, and that it was "just burning in Indonesia".
It was only after he started studying haze hot spots in university that he realised local consumers have a major part to play in preventing them.
Mr Kavickumar, 27, joined the Singapore Environment Council (SEC) as its head of eco-certification shortly after graduating from the National University of Singapore in 2013.
When the haze enveloped Singapore again last year, the SEC, led by executive director Edwin Seah, took the unprecedented step of asking major retailers to declare that they did not sell products from alleged haze culprits.
Last September's move, sparked by the National Environment Agency (NEA) naming firms it was investigating over the haze, forced companies to reconsider their supply chains and placed the fight in consumers' hands.
The SEC, a non-governmental organisation (NGO), administers the Singapore Green Labelling Scheme to endorse eco-friendly products.
It was a bold move for Mr Seah, 45, who had just been appointed as executive director in April, but he felt "assured" of what the group was doing. "We had to act to protect the integrity of our Green Label, to protect our clients who had committed to procuring their paper and pulp from sustainable sources," he said.
The SEC went on to release the names of companies which signed the declaration, and suspend the Green Label of the local distributor of Asia Pulp and Paper (APP), one company named by the NEA.
These actions swiftly began making themselves felt, as supermarket chains such as FairPrice and Sheng Siong began pulling APP products off their shelves.
Mr Seah said the efficacy of their actions surprised him at first. But messages of support started pouring in from the public, which the team drew encouragement from.
"We wanted to convey to consumers that what they purchased had a link to the haze, and that it was in their power to send a strong message to manufacturers that they would not support unsustainable products," he said.
Mr Kavickumar said there was a spike of between 10 per cent and 20 per cent in the number of companies inquiring about certification by the SEC. The group was even contacted by foreign media which wanted to cover its efforts.
He hopes the success will encourage other NGOs. "If they believe in a cause, they should keep pushing. You can become a stepping stone to galvanise change."
Next month, he will be going to haze hot spots in Indonesia as part of a master's course in environmental management, which he is studying for on a part-time basis, on top of his work with the SEC.
Will the haze return this year? Mr Seah said he would not bet against it, adding: "It's a problem that spans decades. But we hope the impact will be less pronounced in terms of intensity."
An "accidental environmentalist" who first joined the SEC as communications director in 2014, he said his concern for environmental issues has deepened because of his role as a father of two children.
"I want them to still have the things we have when they grow up," he said. "You could have the strongest economy, but if the environment messes up, you can kiss your nice lifestyle goodbye. Now skies are clear and the air is clean, but people should not forget."