New Delhi: Even remote Himalayan regions once considered largely untouched by human activity are now showing signs of air pollution, according to a new
study conducted by researchers from the Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute under the Department of Science and Technology (DST).
The study focused on Munsyari, a high-altitude tourist destination in Uttarakhand, where researchers monitored non-methane hydrocarbons (NMHCs) over a one-year period between 2022 and 2023.
NMHCs are reactive gases released from sources such as fuel consumption, vehicle exhaust, and other human activities. They play an important role in the formation of ozone and secondary aerosols, both of which can affect air quality, climate, and human health.
Pollution reaches remote Himalayas
Researchers selected Munsyari because it offers a unique setting to examine the effects of local human activities, including tourism, alongside pollution transported from other regions.
The findings showed clear seasonal variations in pollutant levels. NMHC concentrations remained relatively low during winter and the monsoon season but increased significantly during spring and autumn.
Vehicles, fuel use major sources
The study identified liquefied petroleum gas (LPG) use, diesel consumption, vehicle emissions, and local construction activities as the main sources affecting air quality in the region.
Researchers found that aromatic hydrocarbons such as benzene and xylene made a major contribution to the formation of secondary pollutants, including ozone. Ozone in the lower atmosphere can harm human health and influence climate patterns.
A comparison with other locations showed that NMHC levels in Munsyari were higher than those recorded at Nainital, another high-altitude Himalayan site. However, pollution levels remained lower than those reported in urban centres such as Haldwani and Delhi.
Long-term cancer risk concerns
The researchers said the findings indicate that human-generated pollution is reaching even isolated Himalayan areas.
While current exposure levels do not pose a major immediate health threat, the study found that long-term exposure to benzene could create a cancer risk above recommended safety limits.
The researchers stressed the need for continuous monitoring and targeted pollution-control measures to protect fragile Himalayan ecosystems and communities from growing environmental pressures.
