Sewage spilling into the streets is one of the risks facing London if its politicians fail to adequately respond to rapid population growth.
The capital's population is increasing by 100,000 every year, and could reach 13.4m by 2050, according to the London Assembly's environment committee.
This will put huge pressure on the city's energy supply, its carbon footprint, the availability of drinkable water and the drainage system in the event of excess rainfall.
London’s demand for water could outstrip its supply by 20 per cent by 2040, and the report said Thames Water projects a shortfall of 41m litres per day without action.
"We cannot forget that these extra people will require space for housing, workplaces and recreation as well as generating higher demand for energy and water," Environment committee chair, Darren Johnson, said.
"In addition to global impacts such as carbon emissions, there will be local pressures like the loss of green space and wildlife habitats and an increase in waste generation. Poorly-planned growth would greatly worsen these issues and reduce Londoners’ quality of life."
London’s total emissions have been cut by 11 per cent, but this is still short of the 17 per cent required by now, the committee said.
Meanwhile, London’s recycling rate flat-lining at 33 per cent and well short of the 2015 target of 45 per cent, it added.