Singapore urged Indonesia to take "urgent measures" to address its forest fires, the result of illegal forest clearing, as severe amounts of air pollution have blown from Sumatra Island to Singapore, causing the worst haze in seven years, according to Arab News.

Skyscrapers in Singapore, including the famous Marina Bay Sands casino towers, were covered in a shroud of haze. The smell of burnt wood hung in the air as the Pollutant Standards Index reached 152 as of 9 p.m. GMT Sunday. That is much higher than the officially designated standard for "unhealthy," which sits at 100, according to the National Environment Agency (NEA).

Singapore hasn't suffered from such high amounts of haze since 2006, when the PSA reached 150, according to statistics from the Ministry of the Environment and Water Resources.

The neighboring country of Malaysia is also suffering from the high amounts of haze drifting in the air. It's become a recurring problem that the nations of Southeast Asia have as of yet, failed to address, despite repeated calls for action to curb the pollution problem.

The NEA "urged the Indonesian authorities to look into urgent measures to mitigate the trans boundary haze occurrence."

The Indonesian forestry ministry said that firefighters are already addressing the fires and water-dropping aircraft would only be deployed if the local governors made a request to do so, which has not yet occurred.

"We hope the governments of Malaysia and Singapore will tell their investors to adopt proper measures so we can solve this problem together," Hadi Daryanto, a ministry official, told Arab News, saying that the palm oil companies in those countries were partially responsible for the pollution.

"The haze situation in Malaysia is going to worsen in the coming days with winds carrying smoke from hot spots in Sumatra," Najib Razak, the Prime Minister of Malaysia, wrote on his Facebook page. "Please reduce outdoor activity and drink a lot of water during this period."

Members of the Association of Southeast Asian Nations (ASEAN), a 10-member regional group that includes all three nations, signed an agreement on trans boundary haze pollution in June 2002, but Indonesia hasn't yet ratified the agreement.