Jakarta. Jakarta’s familiar battle with water returned on Monday as hours of torrential rain flooded streets, delayed flights, and brought parts of the world's largest city by population to a standstill.

At Soekarno-Hatta International Airport, the Big Durian’s main aviation hub, heavy rain forced airlines to delay departures as a safety precaution. Airport operator officials said operations continued, but crews moved cautiously as weather conditions worsened through the morning.

“Delays did occur due to bad weather. Our priority is always flight safety,” said Yudis Tiawan, assistant deputy for communication and legal affairs at Soekarno-Hatta.

Lion Air was among the carriers affected between 8 a.m. and 10 a.m., with several flights departing from Terminal 1 gates B2, B4 and B5 delayed by up to three hours. In many cases, aircraft were late arriving in Jakarta after being diverted to other cities when weather deteriorated at their original destinations, creating a ripple effect across the schedule.

Passengers bound for Pontianak, Makassar, Surabaya, and Denpasar waited as incoming planes landed hours behind schedule. Airline staff urged travelers to monitor official updates and remain at the airport, stressing that weather-related disruptions were beyond the carrier’s control.

Outside the terminal, water pooled on access roads leading to the airport, including the Sedyatmo Toll Road at kilometer 33. Floodwater about 20 centimeters deep covered the left lane, slowing traffic to a crawl as drivers eased through the submerged stretch to avoid stalled engines. Police said queues stretched up to 1.5 kilometers, though the route remained passable.

“The road can still be used, but vehicles must reduce speed,” said Sularno, head of traffic at the airport police unit. Officers and disaster management teams were deployed to manage traffic and pump out standing water.

The rain’s impact extended far beyond the airport. In central Jakarta, flooding along Mangga Dua Raya and the Gunung Sahari area forced several offices to shut temporarily after access roads became impassable. Public transport failed to reach the area, leaving workers stranded.

Farhan, an office employee, said he made it close to his workplace only to find it closed. “I’m confused,” he said. “The office is shut because of flooding, but getting home is also difficult. No buses can get through.”

In the north of the city, the economic fallout was even more pronounced. Heavy rain inundated key logistics corridors around Tanjung Priok, Indonesia’s busiest seaport, disrupting the flow of goods in and out of Jakarta.

Adil Karim, chairman of the Jakarta chapter of the Indonesian Logistics and Forwarders Association (ALFI), said flooding around port access roads and warehouse districts had effectively halted operations for many companies.

“At the moment, the area around the port is still flooded,” Adil said. “Our members are struggling to get through, and activities have not been able to resume.”

He estimated that some 1,600 logistics firms affiliated with ALFI Jakarta were affected, with trucks unable to move and containers stranded. Prolonged inundation, he warned, also raised the risk of damage to goods stored in containers, particularly if seals were not fully watertight.

“If the rain eases, the water usually recedes and activities can restart,” Adil said. “But for now, everything is on hold.”

Residential areas were not spared. In Kampung Melayu, East Jakarta, floodwaters rose to about one meter in some neighborhoods, forcing residents to retreat to upper floors of their homes. Local community leaders said water levels began rising early in the morning, though no evacuations had been ordered as of midday.

The United Nations last November named Jakarta the world’s most densely populated metropolitan area, projecting its population at 42 million and overtaking Tokyo for the first time in decades — a claim disputed by the city administration, which said the figure includes millions of commuters across the greater Jakarta region. The city administration estimates Jakarta’s population at about 11 million in 2025.

The flooding came as Jakarta Governor Pramono Anung inaugurated the Cilangkap Batu Licin Reservoir in East Jakarta, a project aimed at strengthening the capital’s flood mitigation efforts. The reservoir is one of nine new water retention basins built by the city administration, designed to increase storage capacity during periods of intense rainfall.

“With nine reservoirs in place, we hope the additional capacity can help reduce the potential for flooding,” Pramono said at the ceremony on Monday.

The Cilangkap reservoir alone can hold about 92,000 cubic meters of water and reaches a depth of six meters. Beyond flood control, it has been developed as a public space with jogging tracks, a basketball court, and a prayer room.

The Meteorology, Climatology, and Geophysics Agency (BMKG) said the risk of heavy rain in Greater Jakarta remains high over the next few days, warning that moderate to heavy rainfall and strong winds could continue through Wednesday across Jakarta, Tangerang, Bekasi, Bogor, and Depok, with some areas under alert for heavy to very heavy rain.