NASA satellite images show thick smog blanketing northern India two days after Diwali

A thick blanket of smog covering large parts of northern India has become visible from space, with satellite images captured two days after Diwali revealing the extent of the pollution crisis gripping the region as winter temperatures begin to fall.

Images available through NASA Worldview, an interactive satellite mapping and visualisation platform, showed extensive grey haze across much of India on November 10, with the most prominent concentrations appearing over the northern states.

The satellite imagery revealed that Delhi, neighbouring Uttar Pradesh and several adjoining regions were enveloped by a dense layer of haze. The visible cover extended northwards towards Uttarakhand, Himachal Pradesh and Jammu and Kashmir.

Parts of central and southern India also appeared under a lighter layer of haze, while western states such as Rajasthan and Gujarat, along with the northeastern region, appeared comparatively less affected in the November 10 imagery.

𝗛𝗮𝘇𝗲 𝘀𝗽𝗿𝗲𝗮𝗱𝘀 𝗮𝗰𝗿𝗼𝘀𝘀 𝗿𝗲𝗴𝗶𝗼𝗻

A comparison of NASA Worldview images from November 9 and November 10 showed a noticeable change in the extent and distribution of the atmospheric haze.

On November 9, a day after Diwali, the visible haze appeared relatively scattered, affecting Delhi, Uttar Pradesh, Bihar and parts of the Himalayan region.

By November 10, the grey cover appeared more widespread, extending across a considerably larger portion of the country.

Satellite observations from November 8, when Diwali was celebrated, had also captured heavy haze over Delhi, western Uttar Pradesh and adjoining northern areas.

The images indicated that the atmospheric haze had persisted across the region despite day-to-day variations in its intensity and geographical spread.

𝗪𝗶𝗻𝘁𝗲𝗿 𝗽𝗼𝗹𝗹𝘂𝘁𝗶𝗼𝗻 𝗰𝗿𝗶𝘀𝗶𝘀

The deterioration in air quality comes amid falling temperatures and seasonal weather conditions that can restrict the dispersal of pollutants.

During winter, weaker winds and atmospheric temperature inversions can trap emissions closer to the ground, allowing pollutants from vehicles, industries, construction activities and agricultural residue burning to accumulate.

Firecracker emissions during Diwali add to the existing pollution burden, contributing to sharp but often temporary increases in particulate matter concentrations.

The satellite observations highlight that the seasonal pollution problem extends beyond Delhi-NCR and affects a much wider geographical region.

However, the visible extent of haze in satellite imagery does not independently establish ground-level pollution concentrations or identify the contribution of individual emission sources.

𝗗𝗲𝗹𝗵𝗶'𝘀 𝗔𝗤𝗜 𝗶𝗺𝗽𝗿𝗼𝘃𝗲𝘀

Despite the widespread haze visible from space, Delhi's air quality registered an improvement on Tuesday, moving into the 'poor' category.

According to Central Pollution Control Board data cited in the report, the national capital recorded an Air Quality Index of 299 on November 10, compared with 376 on November 9.

The improvement was attributed partly to an increase in wind speeds, which helped disperse accumulated pollutants.

Under India's AQI classification, readings between 201 and 300 fall in the 'poor' category, while those between 301 and 400 are classified as 'very poor'. Readings between 401 and 500 indicate 'severe' air quality.

Although the overall AQI declined, pollution levels remained elevated, posing continuing health concerns for residents, particularly children, elderly people and those with respiratory or cardiovascular conditions.

The satellite images underscored the geographical scale of the pollution episode, with large parts of northern India continuing to experience persistent atmospheric haze even as air quality readings in the national capital showed some improvement.