Delhi air quality improved during the summer months is showing worrying signs of deterioration this year. The Air Quality Index (AQI) has consistently remained in the low to mid-200 range and, on some occasions, has even crossed the 300 mark, prompting concerns among environmental experts and researchers.
Historically, such pollution levels have been associated with winter months when crop residue burning, low wind speeds, and temperature inversions trap pollutants close to the ground. However, experts say the current situation points to a growing environmental problem linked to the degradation of the Aravalli mountain range.
Meteorologists have identified dust transported from the deserts and semi-arid regions of Rajasthan as a major contributor to the rising pollution levels in Delhi and the National Capital Region (NCR). Hot and dry winds moving across northwest India are carrying large amounts of dust particles into the region.
For centuries, the Aravalli hills acted as a natural barrier that slowed down these winds and prevented significant quantities of desert dust from reaching the plains. However, environmental degradation over recent decades has weakened this protective shield.
“The Aravalli hills, including both the major mountain ranges and the smaller hill systems, play a crucial role in controlling the movement of sand from the Thar Desert,” explained forest analyst Chetan Agarwal. According to him, the hills traditionally slowed down strong western winds, causing sand and dust to settle before reaching densely populated areas.
Mining and Urban Expansion Taking a Toll
Environmental experts point to extensive mining, quarrying, and rapid urbanisation as key reasons behind the declining health of the Aravallis. Large scale extraction of minerals, including lead-zinc, marble, sandstone, and other industrial resources, has significantly altered the landscape.
A recent study conducted by researchers from the Jindal School of Environment and Sustainability (JSES) and the Indian Institute of Technology (IIT) Kharagpur revealed the extent of these changes. The study found that built-up areas across the Aravalli region increased by 53 percent between 2017 and 2024.
During this seven-year period, approximately 2,644 square kilometres of land were converted for urban development, largely replacing croplands and grazing areas. Researchers warn that such land use changes have reduced the region’s natural ability to absorb dust and maintain ecological balance.
When the study was released earlier this year, experts highlighted that the high number of active mining leases in the Aravalli region continues to place significant pressure on the fragile ecosystem. Mining activities cause geomorphic disturbances that weaken the hills and contribute to habitat loss, soil erosion, and increased dust generation.
Environmentalists warn that if current trends continue, Delhi and neighbouring regions could face increasingly frequent episodes of dust driven pollution, even outside the traditional winter season.
Experts stress that protecting and restoring the Aravallis is critical for improving air quality across northern India. They recommend stricter regulation of mining activities, restoration of degraded landscapes, increased afforestation efforts, and stronger enforcement against illegal encroachments.
As climate change and rapid urban expansion continue to reshape the region, preserving the Aravalli ecosystem may prove essential not only for biodiversity conservation but also for safeguarding millions of people from worsening air pollution in the years ahead.