Watch | The alarming threat rising sea level could pose to Mumbai

With an enviable coastline, a booming economy and a population of more than 20 million to boot, what can threaten a mega city like Mumbai? A lot, if climate experts are to be believed. Climate activists have long been raising alarms about Mumbai's rising sea-level posing a major threat to the city.

If the earth were to get warmer by 4 degrees Celsius (39 degrees Fahrenheit), then Mumbai's iconic monument, the Gateway of India would already be half-submerged in water, according to the projections made by climate experts at Climate Central.

Sea level rise is a direct consequence of melting glaciers and ice, which in turn is a consequence of carbon emissions, global warming and unchecked pollution.