Enhancing Resilience to Poor Air Quality in India’s Economic and Political Hub

Industrialisation in the Delhi National Capital Region (Delhi-NCR) has led to a massive increase in air pollution and urban heat island effects. These two threats compound each year and are deeply detrimental to the economy, public health, and environment in this important region of India. Open wastelands–characterised as barren or exposed soil–could be exacerbating air pollution in the Delhi-NCR.

A group of researchers at the Indian Institute of Tropical Meteorology have developed the Air Quality Warning and Integrated Decision Support System for Emissions (AIRWISE), to predict city-scale air pollution events and provide warnings and mitigation scenarios to residents and planners. The tool is now being enhanced with public Earth Observation data, to better understand and model the widespread impacts of open wastelands. This project has two objectives to support regional urban planners and policy-makers:

These efforts to improve the existing AIRWISE toolkit using Earth Observation are supported by the European Space Agency and Future Earth’s Joint Program.

The Delhi-NCR is home to 46 million residents, and serves as the economic and political centre of India. The region has experienced rapid expansion and urbanisation, and subsequently, an increase in urban heatwaves and air pollution. While they are at their worst in winter, pollution levels in the Delhi-NCR cause excess deaths annually due to exposure to elevated harmful particulate matter, on average equivalent to smoking 9 cigarettes per day. Heatwaves further contribute to air pollution by increasing surface ozone. And these are not just medical emergencies; schools and businesses have to close, and productivity can drop by 19–40%, massively impeding economic progress every year.

The effects of both extreme heat and poor air quality are felt disproportionately by poorer and weaker residents as well, as they tend to spend more time outdoors with less access to air conditioning and air purifiers. The increased use of these appliances, while offering temporary relief, can further exacerbate the negative impacts by putting pressure on the electrical grid and further increasing air pollution from power plants. If left unaddressed, these cascading effects will only worsen with climate change.

Open wasteland sites across the Delhi-NCR (defined as barren or exposed soil) act as a significant dust source in this region, contributing to particulate matter pollution and local heat stress. However, it is still unclear where these sites are, how they are changing over time, and how much their dust may be exacerbating air pollution and urban heat island effects.

The AIRWISE system (Figure 3) incorporates two types of workflows: the Air Quality Early Warning System and the Decision Support System.

The results of both workflows are disseminated on a web platform as geospatial data products and India Meteorological Department bulletins. To map NCR wastelands, machine learning algorithms like Random Forest and weka KMeans model classifiers have been applied, followed by an accuracy assessment. Google Earth Engine is being used to enable rapid and repeatable data acquisition and an operational early warning and decision support framework.

A number of inputs are fed into the toolkit:

To improve the accuracy of the study, the team first updated the land use information for the Delhi-NCR region using recent Sentinel-1 and Sentinel-2 satellite data from 2021, instead of the older 1992 dataset. The finer detail of the newer satellite imagery gives a better picture of current land conditions. Open barren land, an important source of dust emissions, was then identified (Figure 4) using supervised machine learning algorithms in Delhi, and unsupervised in other districts, to understand the distribution and impact of these dust sources.

Figure 5 shows the level of dust concentration in Delhi-NCR from the open barren/wasteland areas identified. The pattern clearly highlights that dust emissions from open barren land regions can significantly increase dust concentrations in the atmosphere both locally and regionally through its regional transport.

Key stakeholders benefitting from the AIRWISE findings include the Commission for Air Quality Management (CAQM), the Central Pollution Control Board (CPCB), the Delhi Pollution Control Committee (DPCC), and the National Disaster Management Authority (NDMA). These bodies are able to use the forecasts and bulletins across the early warning system to respond and protect residents accordingly. The decision support system then allows local and regional authorities to test and implement adaptation solutions, such as increasing vegetation cover or installing natural or artificial air-filtering infrastructure. By enabling timely and targeted interventions—such as emission control measures and public-health restrictions—this system has demonstrated a clear operational benefit in reducing extreme pollution events. Notably, it helped cut peak pollution levels in Delhi by about 18–22% during a severe episode, highlighting its effectiveness in mitigating the intensity of high pollution periods. This ability to proactively “cut the peaks” significantly reduces public exposure during the most hazardous conditions and strengthens overall air quality management. The Commissions for Air Quality Management (CAQM) in the National Capital Region and the adjoining areas, which is responsible for managing air quality in the city of Delhi, has recognized the AIRWISE system as a key partner in a new investigative initiatives to reduce particulate matter pollution and improving air quality in extreme circumstances.

The ESA and Future Earth funded stage of the project aims to inform urban planners, policy-makers, and the general public, to what extent open wastelands are contributing to poor air quality, and provide a series of adaptation scenarios for greening these wastelands. Through the Earth Observation-driven analysis, the project will enable planners and decision makers to design more informed, targeted interventions to effectively reduce air pollution in the Delhi-NCR.

The satellite-driven system can simulate over a large enough region to accurately forecast air quality by accounting for regional weather-related forcings. But the coupling of Earth Observations with ground-based sampling stations and a variety of data resolutions means these forecasts can be delivered at street-scale, where it really matters.