A combination photo shows the clear skyline taken April 25, 2010 and hazy skyline taken June 18, 2013, of the Marina Bay Sands in Singapore. — Reuters Photo
A view from Mount Faber hill shows low visibility due to haze. — AFP Photo
A cyclist rides along the pier in front of buildings blanketed by haze in Singapore. Singapore's Pollutant Standards Index again shot above the "unhealthy" threshold of 152. — AFP Photo
The Marina Bay Sands casino and resort is pictured on a hazy day in Singapore June 18, 2013. — Reuters Photo
Visitors take photos at an observation deck of Marina Bay Sands Skypark overlooking the haze covered skyline of Singapore. — Reuters Photo
A combination photo shows the Singapore skyline on a clear day (top) on April 25, 2013 and on a hazy day June 17, 2013. — Reuters Photo
Workers take a break in front of the hazy skyline of Singapore June 17, 2013. — Reuters Photo
A man walks past the new National Stadium under construction on a hazy evening in Singapore June 17, 2013. — Reuters Photo
A woman wearing a face mask walks in the hazy central business district of Singapore. — Reuters Photo
A view of the highway leading out of the central business district as buildings are blanketed with haze. — AFP Photo
A view from Mount Faber hill shows residential and commercial buildings shrouded in haze in Singapore. — AFP Photo
A man fishes on a breakwater along East Coast Park on a hazy day in Singapore June 17, 2013. — Reuters Photo
Singapore's worst air pollution in 16 years sparked diplomatic tension on Tuesday, as the city-state urged Indonesia to provide data on company names and concession maps to enable it to act against plantation firms that allow slash-and-burn farming.
The haze worsened on Monday with the Pollutant Standards Index (PSI) hitting 105 at 3pm according to local media.