Heavy rains lashed Mumbai after the annual monsoon arrived in India’s financial capital nearly two weeks before schedule, according to weather forecasters.

The downpours, which have brought relief from high temperatures and are welcomed by farmers for their crops, also wreak havoc in urban areas every year by flooding transport infrastructure. Typically, such monsoon rains are expected across the southwestern state of Maharashtra in early June.

The Indian Meteorological Department (IMD) has warned of “extremely heavy rainfall” in Mumbai, while city authorities have issued a red alert in place until Tuesday.

“All citizens are advised to stay indoors and avoid travel unless necessary,” the city authorities said in a statement, urging people to “kindly cooperate”.

In a statement, the IMD said the rains had reached Mumbai on Monday, “16 days earlier than usual”, with the monsoon normally expected to arrive about 11 June. This, the agency noted, is the earliest onset for nearly a quarter of a century.

“This marks the earliest monsoon advancement over Mumbai during the period 2001-2025,” it said.

Across Maharashtra, regional IMD chief Shubhangi Bhute confirmed it was the earliest arrival of the monsoon in 14 years.

South Asia has experienced rising temperatures in recent years, accompanied by shifting weather patterns, but scientists remain uncertain about the precise effect of global warming on the region’s highly complex monsoon system.

The southwest monsoon, a colossal sea breeze, delivers between 70 and 80 percent of South Asia’s annual rainfall between June and September each year. It is triggered when seasonal heat warms the subcontinent’s landmass, causing air to rise and drawing in cooler winds from the Indian Ocean, releasing huge volumes of rain.

The monsoon is crucial for agriculture and, by extension, the livelihoods of millions of farmers and overall food security. But it also brings annual destruction in the form of landslides and floods.