‘Like standing next to a chainsaw’: Delhi slums near railway lines bear the brunt of loud trains

“This is a public health emergency brewing in Delhi’s most marginalised communities,” said Rajeev Mishra, associate professor at DTU’s Department of Environmental Science and Engineering, who led the research team.

The study identified freight trains as the biggest contributors, producing average noise levels of 100.1 decibels, which is nearly double the CPCB’s residential limit of 55 decibels.

Diesel locomotives were consistently noisier than electric ones, generating 2-8 decibels more sound across all categories of trains.

Across all train types, including passenger, express, superfast, and freight, electric engines emitted less noise. Electric express trains recorded the lowest average levels at 91.8 decibels.

“People living in slum clusters right next to the tracks face higher risks, as their proximity leaves them directly exposed,” Mishra added.

According to the study, the noise levels varied sharply by location. For instance, Patel Nagar Railway Station (PTNR) recorded the highest levels at 120 decibels, comparable to standing next to a chainsaw, the study noted.

Shahdara (DSA) was the lowest at 69.1 decibels — but still 26 per cent above safe thresholds.

Researchers attributed these differences to track geometry, with straight-line stretches enabling faster train speeds and, consequently, greater noise.

The analysis also revealed time-linked patterns: noise peaked between 1 pm and 5 pm, when train frequency was at its highest. During these hours, certain sites recorded spikes of up to 115.6 decibels. The study found a statistically significant correlation between the number of trains and the intensity of noise across all monitored locations.

Health concerns

The current noise levels are far above World Health Organisation guidelines, which warn of health risks such as disturbed sleep, cardiovascular disease, and cognitive impairment when exposure exceeds 55 decibels, the study noted.

Delhi’s 775 slum clusters — of which 67 (9.9 per cent) lie on or directly next to railway land — house around 3,06,521 families who endure daily exposure without adequate safeguards, it added.

The research points to locomotive electrification as a mitigation pathway, underlining that switching to electric operations could deliver immediate improvements.

Recommendations

The team has recommended urgent noise-control measures: building sound barriers, limiting diesel train operations in densely populated areas, and rerouting freight traffic away from residential zones.

Using Geographic Information System mapping, the study also identified specific hotspots that require targeted interventions.

In its recommendations, the researchers have also called for slum-sensitive planning and acoustic safeguards to reduce chronic exposure.

As Delhi expands rapidly, the study has underlined that protecting vulnerable communities must be a policy priority. It also recommends targeted noise mitigation strategies to significantly improve living conditions for residents.