Indonesia's Environment and Forestry Minister Siti Nurbaya Bakar has again declined Singapore's assistance to fight the haze.
She reportedly told CNN Indonesia yesterday that her country is still trying to handle the crisis on its own.
This, however, appears to be a U-turn on an earlier invitation by Vice-President Jusuf Kalla for Singapore to help. "Singapore is ready to help, so I think please do," said Mr Kalla in Jakarta on Tuesday.
The haze, caused by illegal forest fires in Sumatra and Kalimantan, has blanketed parts of Indonesia, Malaysia and Singapore in recent weeks.
Singapore's Defence Minister Ng Eng Hen said last Friday that Indonesia had accepted an offer from Singapore to help combat the fires but that was turned down a day later by Ms Siti, who said Indonesia had enough resources. Singapore's offer was renewed again on Monday - this time, she told Environment Minister Vivian Balakrishnan that she would reconsider.
The latest reversal comes after Indonesia revealed a wide-ranging plan to tackle the haze crisis, which includes deploying more troops and police to help with fire-fighting and stepping up cloud-seeding operations to douse the blazes.
Meanwhile, Singapore's National Environment Agency (NEA) said cloud seeding to clear the air of haze has not been, and will not be, done here as its effectiveness is doubtful.
"Cloud seeding requires existing clouds as it cannot generate rain out of thin and dry air," it said on its website yesterday. "During dry seasons, cloud seeding is less effective due to the lack of suitable clouds.
"The small size of Singapore and the variability of winds also mean that the induced rain, if any, may not fall directly over our island."
Rumours have been circulating that cloud seeding is being carried out to reduce the impact of haze for the Formula One race this weekend.
The rumours, spread on messaging app WhatsApp, implied that the resulting rain was harmful, and urged people to keep away from "chemically induced rain showers".
Dr Balakrishnan has also reiterated the point in a Facebook post saying: "NEA does not engage in cloud seeding and has no plans to do so."
Cloud seeding is an attempt to induce rain by introducing chemicals such as silver iodide into clouds. It has been done in Malaysia and Indonesia, where haze has caused air quality to reach hazardous levels.
Dr Erik Velasco, a research scientist from the Singapore-MIT Alliance for Research and Technology, said that while silver is considered a pollutant, its input by cloud seeding is "negligible compared with the contribution of other emission sources such as refineries, power plants... and even (road) traffic".
He said it does not cause acid rain.
Air quality further improved yesterday, with the 24-hour Pollutant Standards Index (PSI) dropping to the moderate range.
As of 8pm yesterday, the 24-hour PSI was 68 to 81. For today, it is expected to be in the high end of the moderate range or the low end of the unhealthy range.
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