People wear masks to protect themselves from the haze that's shrouding the Singapore Flyer and Marina Bay Sands on Sept. 29, 2015. Singapore's banks are taking steps that may tighten funding for companies linked to the Indonesian forest-burning that causes the haze. Reuters

Singapore's banks have approved loan criteria that could be used to deny funds to companies linked to the haze from Indonesia that's polluting the city state's air.

The 158-member Association of Banks in Singapore approved guidelines to include greenhouse gas emissions, deforestation, forest degradation and biodiversity loss among the criteria for granting loans, Agence France-Presse reported. The criteria would apply to the forest-burning that's causing the haze.

Indonesia burns forests every year to make way for palm-oil tree and paper plantations, and winds carry the smoke to Singapore, Malaysia and Thailand. On Thursday, Indonesian President Joko Widodo did an about-face and said he would accept help from Singapore, Malaysia, Japan and Russia to stem a problem he said could take three years to fix.

The banks' action follows a suit Singapore filed against five companies linked to the forest-burning two weeks ago.

Singapore's biggest supermarket chain, NTUC Fairprice, also stopped selling products of Asia Pulp & Paper, whose suppliers are suspected of involvement in some of the forest-burning.