With the city-state of Singapore enveloped in a thick smokey haze from burning forest fires in neighbouring Indonesia, the Civil Aviation Authority of Singapore (CAAS) has closed the island’s second airport – Seletar Airport which operates under visual meteorological conditions – to all departing and arriving flights as a result of prolonged poor visibility caused by the haze.The closure on Thursday from 11AM to 11PM was subsequently extended to 2PM Friday as the Runway Visual Range (RVR) fluctuated bewtween 700 and 1,200 metres, below Seletar’s minimum operating requirement of 1,500 metres.

Meanwhile over at the the main Changi Airport gateway the RVR has been fluctuating between 650 and 1,600 metres which has prompted air traffic controllers to increase the time between takeoffs and landings because of the visibility concerns. The RVR is a measurement of the horizontal visibility along the runway or the range over which the pilot of an aircraft can see along the runway. The CAAS added that the move was simply a precautionary step and Changi Airport has facilities and procedures to allow safe landing of aircraft in low visibility conditions in accordance with international standards. There had not been any significant delays in flight departures and arrivals the CAAS added.

During the prolonged period of haze in 1997, the lowest RVR reading at Changi Airport was about 800 metres. By late morning on Friday, the Pollution Standard Index (PSI) reading reached an alarming record high of 400 (a three hour average reading), far exceeding 1997’s high of 221. A PSI reading of 300 is classified as ‘hazardous’ to people’s health, particularly those with respiratory ailments. The Singapore authorities meanwhile, urged people to remain indoors amid unprecedented levels of air pollution Thursday and neighbouring Malaysia closed 200 schools.