Extent of the Rainfall

Heavy Monsoon Showers Across Delhi, Mumbai and Andhra Pradesh: Immediate Impacts and Seasonal Context

The India Meteorological Department (IMD) recorded intense rain on July 5‑6 2026, with Delhi’s Chhatarpur receiving 49 mm, Mumbai’s suburbs exceeding 250 mm in 23 hours, and heavy showers spreading over Jharkhand, Rajasthan and the north‑coastal districts of Andhra Pradesh. The deluge forced the cancellation of four IndiGo flights, diverted 13 aircraft, and prompted a red‑alert for Mumbai and Raigad district, underscoring how a single weather system can strain urban infrastructure and aviation networks.

Delhi’s capital region saw the highest single‑day total of 49 mm at Chhatarpur, while Gurugram logged 35 mm and Mehrauli 18 mm. In Mumbai, the IMD’s rain gauge network reported more than 300 mm in some suburbs, triggering the city’s first‑ever three‑hour red alert. Along the north‑coastal belt of Andhra Pradesh, isolated places were forecast to receive up to 100 mm, and Jharkhand districts such as Garhwa and Ranchi were flagged for heavy rain.

• ▸Chhatarpur (Delhi) – 49 mm recorded by 2.30 p.m. on 5 July.
• ▸Mumbai suburbs – > 250 mm in 23 hours, prompting runway shutdown.
• ▸Gurugram (Delhi) – 35 mm, the second‑largest reading in the capital region.
• ▸North‑coastal Andhra Pradesh – forecast of 100 mm at isolated stations.
• ▸Jharkhand (Garhwa, Ranchi) – heavy‑rain warnings for 6 districts.

Why the Monsoon Intensifies Now

The current episode is driven by the seasonal Southwest Monsoon, which draws moist air from the Indian Ocean onto the subcontinent each June‑September. A low‑pressure system that formed over the northwest Bay of Bengal at 21.1° N, 87.2° E intensified into a depression on 5 July, moving west‑northwestward toward the Odisha coast. The IMD’s forecast of gusts up to 50 km h⁻¹ and thundershowers reflects the interaction of this depression with the prevailing monsoon flow.

• ▸Depression centre – 21.1° N, 87.2° E, about 50 km SSE of Balasore.
• ▸Wind speeds – 40‑50 km h⁻¹ over isolated coastal spots in Andhra Pradesh.
• ▸Rainfall forecast – light to moderate showers across the north‑coastal belt, heavy rain at isolated points in Srikakulam and Vizianagaram.
• ▸Monsoon onset – the Southwest Monsoon entered the Indian subcontinent on 30 May 2026, advancing steadily northward.
• ▸IMD’s role – the Indian Meteorological Department issues real‑time warnings and maintains the national rain‑gauge network.

The Köppen climate classification places much of the affected region in the “Tropical Wet and Dry” (Aw) zone, where monsoon rains dominate the annual precipitation budget. Variability in the Central Indian Basin—the heartland of the monsoon’s moisture plume—has risen by 15 % in recent years, amplifying the risk of extreme events.

Geographical Vulnerabilities

Delhi’s low‑lying floodplains, combined with inadequate drainage, turn even moderate rain into urban flooding. Mumbai’s coastal location on a reclaimed peninsula makes it susceptible to storm surges, while the north‑coastal districts of Andhra Pradesh sit on narrow alluvial strips that lack natural buffers. These physical constraints intersect with rapid urbanisation, creating hotspots where infrastructure cannot keep pace with climate‑driven hazards.

• ▸Delhi’s Yamuna floodplain – elevation ≤ 200 m, prone to waterlogging.
• ▸Mumbai’s reclaimed islands – average elevation ≈ 3 m above mean sea level.
• ▸Andhra Pradesh’s coastal belt – width ≈ 10‑15 km, limited hinterland for runoff absorption.
• ▸Urban drainage capacity – Delhi’s storm‑water network handles only 150 mm h⁻¹, below the recorded intensity.

Implications for Disaster Management

The simultaneous activation of multiple warning systems—IMD’s heavy‑rain alerts, the National Disaster Management Authority’s (NDMA) red‑alert for Mumbai, and the Andhra Pradesh State Disaster Management Authority’s (APSDMA) high‑alert for the north‑coastal region—highlights the need for coordinated response. In Mumbai, the Brihanmumbai Municipal Corporation (BMC) struggled to clear clogged storm‑water drains, while the airport’s runway shutdown caused an average departure delay of 65 minutes for 90 % of outbound flights.

• ▸Flight disruptions – 13 incoming aircraft diverted, 90 % of outbound flights delayed by ≈ 65 minutes.
• ▸BMC’s drainage backlog – over 1 million cubic metres of water stalled in clogged canals.
• ▸NDMA red‑alert – issued for Mumbai and Raigad district for a three‑hour window on 5 July.
• ▸APSDMA high‑alert – activated for north‑coastal Andhra Pradesh, mobilising