The heavy rainfall pounding Indonesian capital Jakarta and its surrounding areas over the New Year period was "not ordinary" and, when combined with the city's overcrowding and overdevelopment problems, led to one of the worst floodings in years - claiming over 40 lives and leaving hundreds of thousands homeless.
The monsoon season and high amount of water vapour in the air were among the reasons for the intense rainfall in Jakarta, which the country's meteorology, climatology and geophysics agency, or BMKG, measured at 377mm on New Year's Eve - the highest daily reading since the agency began publishing data in 1996.
During the previous massive flooding in 2007, rainfall intensity had reached 340mm a day.
"The extreme rain event is not ordinary. The probability of its occurrence is once in a century. It is very rare," Professor Rizaldi Boer, a climate change expert from Bogor Agricultural University, told The Straits Times.
"One possibility is that Indonesia had experienced a prolonged dry season due to the El Nino phenomenon. So, the high temperature has led to greater evaporation in the atmosphere which, in turn, resulted in the high amount of water vapour and the intense rain now," he added.
While climate change has disrupted weather patterns, Jakarta's rapid urbanisation, uncontrolled population growth, excessive extraction of groundwater for drinking and household purposes, as well as poor sanitation and drainage systems, may have contributed to the catastrophic flood, climate change and urban planning experts told ST.
The recent flooding may lend some credence to President Joko Widodo's proposal last August to move the administrative capital to the sparsely populated East Kalimantan province on Borneo Island in order to relieve overcrowding in the megacity of 10 million, which is purportedly sinking at a rate of 1cm to 15cm a year.
"It is time to move because the huge population can't all fit in Jakarta," said public policy analyst Agus Pambagio from the University of Indonesia. "We must find a new centre of economics. Shifting the capital may not be the easiest thing to do, but it is the best alternative."
But some analysts say this is not a be-all-and-end-all solution, but rather points to the need for more optimal land-use planning of open spaces and a better drainage system.
"Only civil servants will move to the new capital, but all the businesses will stay in Jakarta. How does this reduce any burden?" said Mr Nirwono Joga, an urban planning expert from Trisakti University. Instead, he suggested clearing squatter settlements and residential areas encroaching the riverbanks, and increasing dredging to clear the canals and waterways of trash and debris.
"Jakarta has 13 rivers flowing through it which provide a natural channel for rainwater to flow into the sea. We need to manage them properly," he said.
He added that more green space on riverbanks will allow for better absorption of water.
Agreeing, Prof Rizaldi said: "Big floods are becoming common. What we need is action to restore the ecosystem and for everyone, not only the government, to work together to control floods."