New Delhi, Nov 12 (PTI) Excess rainfall and flooding could be responsible for more than eight per cent of total deaths during Mumbai's monsoon every year, with slum residents bearing over 80 per cent of the
burden, a study has estimated.
The figure of eight per cent translates to around 2,300 to more than 2,700 lives lost per year. Children face the biggest increase in death risk in the wake of extreme rainfall and flooding, while women are at a higher risk compared to men, according to findings published in the journal Nature.
Researchers from the US' institutes, including Princeton University and Green Globe Consulting in Mumbai, said inadequate infrastructure such as a poor drainage system can worsen the impacts of extreme weather events and pose a threat to people living in urban areas.
As warming of the planet continues and more people settle in flood-prone areas, understanding how rainfall and sea-level rise can influence public health is crucial, they said.
The team analysed death records and rainfall data in Mumbai during 2006-2015 to gauge the mortality rate following an excess rainfall -- for instance, days with 150 millimetres of rain -- and flooding.
"We find that rainfall causes more than eight per cent of Mumbai's deaths during the monsoon season, and that more than 80 per cent of this burden is borne by slum residents," the authors wrote.
"Children face the biggest increase in mortality risk from rainfall, and women face a greater risk than men," they said.
Further, 150 millimetres of rainfall in a day causes an increase of 2.2 per cent in the general mortality rate -- 2.9 per cent among slum residents -- in Mumbai in the five weeks that follow, the team found.
The result could be attributed to mechanisms including the spread of flood-related diseases, such as dengue, malaria and typhoid, in the wake of the storm, they said.
The estimates are the first of its kind population-level ones revealing disparities in rainfall-related deaths within a city, the authors said.
They added that the findings of deaths related to rainfall are larger than what is documented in official statistics, highlighting that an investment in improved drainage, sanitation and waste management is urgently needed.
The team also estimated that the mortality costs of rainfall in Mumbai are about USD 1.2 billion per year.
Death risk due to rainfall was seen to increase sharply during a high tide, which the researchers said presents a channel through which rising sea levels amplify the effects of a high tide and contribute to excess deaths.
For example, 30 millimetres of rainfall causes a 0.95 per cent increase in five-week mortality if it happens when the tide level is predicted to be 416 centimetres (high tide), but only a 0.12 per cent increase if the rain falls during an hour when the tide level is predicted to be 94 centimetres (low tide), the authors explained. PTI KRS KRS KSS
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