By Payal Kapadia in Mumbai
Why does a week of heavy monsoon rain kill more than 400 people, cause damage estimated at nearly $700m, and completely paralyse life in a bustling metropolis?
The rain shut down life and work in Mumbai
Shocked residents of Mumbai (Bombay), India's financial and film capital, have been asking this question after the deadly deluge in their city made headline news all over the world.
The politicians who rule the city and the state of Maharashtra blame it on the weather - this was record rainfall caused by a freak cloudburst, they say, and it took the government by surprise.
"What a load of bunkum!" says Mumbai-based urban planner Chandrashekhar Prabhu.
No one disputes that the island city on the Arabian Sea had more than its share of rainfall recently - some parts of the suburbs are reported to have received 94cm (37 inches) of rain in a single day last week.
The high tide also did not help matters.
Mumbai's storm water drains are designed to shut during high tide.
This prevents tidal water from entering the city, but on very rainy days, it also prevents rainwater from draining out.
"But the water that collected in the city should have ebbed when the tide receded," says Bittu Sahgal, one of India's best-known writers on environmental issues.
"Why didn't that happen?"
Mr Sahgal blames the Bandra-Worli Sea Link, an ambitious flyover project that has come under fire from environmentalists for making ecological compromises.
The flyover crossing the sea, he says, has pinched the mouth of the Mithi River that drains most of Mumbai's excess water out into the Arabian Sea.
That's not all.
The systematic destruction of about 1,000 acres of the city's mangrove cover - what's left, about 5,000 acres, is under threat - has deprived Mumbai of its natural flood-barrier and silt trap.
Now rainwater washes silt into the bay, threatening to clog the city's deep natural harbour.
Large parts of the city are under water
"Ecologically unsound decisions have caused huge financial damage," says Mr Sahgal.
Maharashtra Chief Minister Vilasrao Deshmukh blamed unprecedented rain for the monsoon disaster.
"What could any government do?
"People panicked... they did not follow instructions and the police were helpless," he told Reuters news agency.
"We will look into the urban development issue, but this is not the time to do it. Our priority now is rescue, relief and rehabilitation."
Horror stories abound of urban welfare projects gone terribly awry.
A World Bank-funded urban transport project has cut away hillsides, dumping debris on the city's wetlands.
Mangroves have been cleared to build golf courses, amusement parks and rubbish dumps.
Building construction is planned even on 5,400 acres of salt pan land.
"In the post-tsunami scenario, this is plain lunacy," says Debi Goenka, executive trustee of Conservation Action Trust, an environmental NGO.
Experts say the historical process of reclaiming the sea to build the city is the cause of Mumbai's problems.
The city's drainage system is in a mess
In the 16th century, 95% of today's Mumbai was under water, says Sheela Patel, director of Sparc, an NGO working on housing issues.
"We can't rectify what happened 100 years ago," admits Bittu Sahgal. "They didn't have the benefit of information that we do."
It's not just the "no-development zones" that have fallen prey to the frenzy of unplanned building.
Successive state governments have signed off lands reserved for parks on the pretext of housing the poor.
In fact, the replacement of low-lying slums with multi-storey buildings has made the city a concrete jungle.
Typically, 35-40% of rainwater is absorbed by the land, lifting groundwater levels, but there are few open spaces left in Mumbai.
India has the lowest ratio of open space to people in the world - a mere four acres per 1,000 of population, compared to the global benchmark of 12 acres.
In Mumbai, this falls to a paltry 0.2 acres, and after accounting for slums, it diminishes to a measly 0.03 acres.
An unholy nexus between politicians and builders and unfettered development has brought the city to the brink of collapse, environmentalists say.
Unregulated development led to landslides
Mumbai's development plan is obsolete in the face of such unfettered urban growth, they allege.
Thousands of tonnes of uncleared rubbish choke the city's 100-year-old storm water drains, which urgently need an overhaul.
And in a city where 88% of commuters use public transport, governments spend a lot on flyovers and a pittance on upgrading creaky trains and buses.
Environmentalists say the only city in the world with a quarter of its land area designated as a national park is on a suicide mission.
Bittu Sahgal calls it "a case study for the collapse of urbania in India".
Can it get any bleaker?
Some experts say that the city is doomed
Debi Goenka certainly thinks so.
If Mumbai's unprecedented rainfall is an early warning of global warming and rising sea levels, the city will "become an island again, be it with rain water or sea water".
In the next 50 years, the storm drains that carry rainwater out of Mumbai could be bringing sea water in, even at low tide, Mr Goenka prophesies.
"People should be moving out of Mumbai, not moving in," he says.
"This city is a sinking ship."