The capital of India, New Delhi, demonstrated unexpected success in the current monsoon. As of September 16, the Haryana meteorological division recorded an 8% surplus of seasonal rainfall, while neighboring districts experienced a deficit of 23%. The wider northwestern region of India showed a deficit of 10%. This unusual pattern of precipitation suggests that the intensification of El Niño and climate change may have contributed to the capital receiving unexpected moisture abundance.
A map of district rainfall across the region shows that Delhi is on the border of a good monsoon zone this year. Directly north of the capital lies a band of districts with insufficient rainfall, starting with neighboring Sonipat (-32%), Rohtak (-47%), and extending to Hoshiarpur (-53%) and Kapurthala (-69%) in Punjab. This zone includes over 30 districts of Haryana, Punjab, as well as adjacent Rajasthan, Himachal Pradesh, and western Uttar Pradesh.
The reason why Delhi became a wet spot next to a drought-stricken area is explained by the shift in the direction of low-pressure systems arriving from the Bay of Bengal this season, likely influenced by El Niño. Furthermore, the unique interaction of these systems with western disturbances has provided significant assistance in the rainfall in Delhi-NCR.
Most of the monsoon rainfall in central and northwestern India occurs under the influence of moisture-laden low-pressure systems, including depressions, which move inland from the Bay of Bengal. However, contrary to expectations, the number of such systems does not decrease in El Niño years. According to a study published in Climate Dynamics in 2024, the number of Bay of Bengal depressions increased during El Niño years between 1979 and 2020, averaging 3.9 during July-August compared to 2.4 in normal years.
This year, 10 low-pressure systems were recorded, including four depressions in July-August, exceeding the norm of less than nine. What usually changes in El Niño years is the direction of movement of these low-pressure systems. IMD Director-General Mrutinjai Mohapatra noted: 'In El Niño years, there is a downward air movement over South India and its adjacent northern parts. This hinders the formation of low-pressure systems in southern latitudes, such as in the central part of the Bay of Bengal, which usually head towards the Andhra Pradesh-Odisha coast in the south.'
This is where Delhi benefited, especially in August, when up to six low-pressure systems affected India, including two depressions. Due to the northward shift, most of these systems penetrated deep into the territory through northern Odisha and Bengal, moving north-northwest, affecting Odisha, Bengal, Jharkhand, Uttar Pradesh, Uttarakhand, and the Delhi region, while the impact on Rajasthan, Haryana, and Punjab was smaller.
Another factor, likely related to climate change, also played a role. Western Disturbances (WDs) are moist wind systems moving eastward from the Mediterranean region that traditionally bring rainy weather to North India in winter and early spring. Historically, WDs are rare during the monsoon period because the jet stream causing these disturbances usually migrates north of the Himalayas by April-May. However, in recent years, the jet stream has consistently delayed its retreat, which scientists attribute to global warming. This year, from June to August, 16 WDs were recorded—eight only in August, according to IMD.
There were several instances of interaction between the eastern monsoon system and WDs, which intensified rainfall in parts of North India, including Delhi. For example, the onset of the monsoon over the capital on July 2 occurred during an active period of WDs. The heaviest rains in Delhi (July 8-9, July 29, August 7-8, August 25) happened when both the monsoon system and WDs were active simultaneously. These interactions also caused heavy rains in western Uttar Pradesh and left a catastrophic mark in the mountains—the landslide at Bandipora (Jammu and Kashmir), deadly flash floods in Chamba (Himachal Pradesh), and the forced closure of about 290 roads in Himachal Pradesh and Uttarakhand; however, they apparently did not have a significant impact on Haryana and Punjab.