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Mumbai Manholes: A Century of Danger and Design
2 Aug
Summary
- Manhole covers in Mumbai have evolved over 100 years to combat theft, corrosion, and accidents.
- Recent deaths have spurred new interventions like protective grills and 'manhole railguards'.
- FRP covers were introduced to deter theft but proved unsafe during heavy rainfall.
Mumbai's manhole covers have seen continuous evolution for over a century, adapting to the city's expanding drainage network and recurring challenges. These challenges consistently include theft, corrosion, flooding, and fatal accidents, prompting repeated redesigns by the Brihanmumbai Municipal Corporation (BMC).
Initially, iron gratings covered manholes for ventilation. By the late 19th century, circular cast iron covers became standard, valued for their durability and tight seal. However, their scrap value led to widespread theft in the early 2000s, with covers being stolen or broken.
In 2008, the BMC experimented with Fibre Reinforced Plastic (FRP) covers to deter theft, but these proved too light and were dislodged during heavy rains. By 2016, ductile iron covers were adopted, offering strength with less scrap value, and FRP covers were phased out.
Following tragic deaths, the BMC introduced hinge-based and chain-linked covers in 2019, but these also failed due to rusting and theft. Smart manholes with sensors were piloted in 2024 but faced technical issues.
Since 2023, protective grills have been installed beneath manhole covers. The latest intervention, a 'manhole railguard,' is a temporary enclosure used during maintenance to prevent falls. The BMC continues its trial-and-error approach to enhance manhole safety.
