Trees are collapsing in the heat — and BMC launches drive to ‘hydrate’ them
After a spate of summer tree falls, including a Khar collapse that injured two girls, the BMC has launched an unusual citywide drive to water mature trees amid fears of heat-induced ‘embolism’ weakening roots and branches.
4 min readMumbaiUpdated: May 14, 2026 07:24 PM IST
Typically, Mumbai experiences cases of tree falls and branch collapses during the monsoon season, triggered by heavy showers and strong winds. (Express Photo)
Days after a tree collapse in Khar critically injured two girls, the Brihanmumbai Municipal Corporation (BMC) has launched a first-of-its-kind drive to water large trees across the city in a bid to reduce heat stress on trees and prevent their weakening.
According to senior officials, the drive was initiated after incidences of tree collapses this summer, due to tree “embolism”, triggered by lack of moisture in soil and weakening of branches amid extreme heat.
Typically, Mumbai experiences cases of tree falls and branch collapses during the monsoon season, due to heavy rain and strong winds. However, an unprecedented increase in tree collapses during summer nudged the civic body to investigate the root cause.
“We observed that extreme heat was leading to loss of soil moisture, thereby affecting tree stability, drying of branches and weakening of root systems. This was increasing the risk of large branch falls and uprooting of trees in many locations,” a senior BMC official from the civic garden cell told The Indian Express.
Scientifically, extreme dehydration in trees is a phenomenon associated with “hydraulic failure” and “embolism” in trees. “During extreme heat, trees open their stomata (leaf pores) to cool themselves through evaporation. However, when soil moisture is insufficient, trees begin drawing water from their internal storage tissues. This creates intense suction within the xylem tissues, causing air bubbles or vapour pockets (embolism) to form, which obstruct water transport inside the tree. As a result, certain branches or sections of the trunk begin drying out,” a civic official said.
With branches becoming brittle and soil drying, the risk of collapses is high. In a bid to check this, the BMC on Tuesday issued directives across departments to carry out watering of adult trees across the city. Initial target would be trees in crowded areas such as railway stations, hospital compounds and bus depots.
According to officials, while trees in gardens and recreational spaces will be watered by the garden department, the Solid Waste Management (SWM) department will undertake watering of trees along roads.
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The civic body has also instructed organisations who maintain plantations within road dividers through CSR funds to carry out watering around their premises. The civic garden cell has instructed citizens to carry out watering within private compounds like residential complexes and surrounding public spaces.
Generally, the civic body carries out plantation of new trees during the pre-monsoon period with the goal of providing them with sufficient watering when monsoon kicks in. While new saplings are watered during summers, mature trees are self-sufficient and are not watered.
“However, we are witnessing unprecedented levels of heat now. Therefore, a decision was taken to launch a watering drive for adult trees till the onset of monsoon,” said an official, adding that each tree would be watered at least once or twice a week.
According to the garden department’s data until March 2025, Mumbai is home to 29.75 lakh trees of which 12.21 lakh trees are in the western suburbs, 10.34 lakh in the eastern suburbs and 7.18 lakh in island city. Of these, over 1.90 lakh are roadside trees as per the last available census records.
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The BMC is also undertaking tree trimming exercise as a part of its pre-monsoon preparedness for which 92,277 trees have been earmarked.
Nayonika Bose is a Senior Correspondent with The Indian Express’ Mumbai bureau. While in the early stages of her career, her focused reporting on local governance and community welfare already demonstrates clear Expertise and Trustworthiness in covering essential civic issues impacting Mumbai's residents.
Expertise & Authority (E-E-A-T)
Specialized Focus: Nayonika's reporting is dedicated to civic and community issues, providing readers with highly relevant, ground-level information about the functionality and administration of India's largest metropolitan area.
Core Coverage Areas: Her articles highlight a strong focus on the fundamental quality of life and public safety in Mumbai, including:
Civic Infrastructure: Reports on critical failures and initiatives related to public works, such as the recurring problem of unauthorized building collapses in Navi Mumbai, the construction of new infrastructure projects (like the Dahisar-Bhayandar Link Road and the Mahalaxmi cable-stayed bridge), and the maintenance of essential city services (e.g., manhole cover theft).
Urban Governance & Crisis Management: Provides detailed coverage of the Brihanmumbai Municipal Corporation's (BMC) response to major crises, particularly during the monsoon (e.g., heavy rainfall, water cuts, and public health concerns like dengue and malaria) and large-scale public safety incidents (e.g., the hoarding collapse fallout).
Community Welfare & Rights: Reports on key social issues, including the financial aid scheme for persons with disabilities, the struggles of Mumbai's hawkers protesting eviction drives, and the dangers faced by workers due to the continuation of manual scavenging in water tanks.
Cultural & Heritage Reporting: Covers significant community stories, including the restoration of British-era fountains and the history of institutions like the 126-year-old Chinchpokli cemetery, showing a breadth of interest beyond pure administration.
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