The death tolls from Thailand's worst floods in more than 40 years have climbed past 500 on Sunday, as pools of polluted water threatened Bankok's subway system, the Associated Press reported.
“The amount of water is massive,” Thailand's Prime Minister Yingluck Shinawatra said after visiting a flooded district on the city’s outskirts, Bloomberg reported.
“It may take two to three weeks for the water to drain to the sea, so we are asking people to be patient.”
Bangkok's governor, Sukhumbhand Paribatra has ordered 11 of Bangkok's 50 districts to be evacuated. The evacuations are not mandatory, and many are staying to protect their homes and businesses.
The district of Chatuchak has become the latest added to the government's evacuation list. Chatuchaka, a tourist destination, is home to a major public park and an outdoor shopping zone.
More from GlobalPost: In flooded Bangkok, shades of Katrina.
Rainfall has plagued Thailand since late July, killing 506 people, according to the latest government statistics, AP reports.
Although no deaths have been reported in Bangkok, 90 people have been reported dead in the neighboring province of Aytthaya has ben submerged under floodwater for more that one month.
Floods are an annual occurrence in Thailand but have been particularly bad this year, prompting some residents and analysts to criticize the government's response.
According to CNN:
"Now the government is sending a mixed signal that the situation is fine, but the truth is it the situation far from over," political analyst Supong Limtanakul said. "It is a slow suffocating death of Bangkok business area."
The unusually heavy monsoon rains have left more than nine million affected and more than a third of the nation's provinces partially flooded, according to news reports.
"Picture the equivalent of 480,000 Olympic-sized pools of water trying to make their way through Bangkok at the moment," Craig Steffensen, Asian Development Bank's country director for Thailand, told CNN.
"Combined with the floodwaters trying to get out and the tides coming in...we could see a perfect storm in Bangkok."
According to AFP, the economic impact of the flooding can already be felt in Thailand. Thousands of inundated factories have been forced to shut down, and more than half a million people in the country are temporarily out of work as a result.
From GlobalPost's Patrick Winn: Bangkok is sinking (interactive map)