UrbanEmissions.Info stands for (a) sharing knowledge on air pollution (b) science based air quality analysis (c) advocacy and awareness raising on air quality management and (d) building partnerships among local, national, and international air-heads.
NCAP was introduced in 2019 to address air pollution in India’s non-attainment cities. The current list of 131 cities are required to document (1) emission and pollution load via monitoring and modelling (2) activities necessary for all the known sources to achieve the pollution target (3) plans to build institutional capacity to manage the information flow and (4) ways to oversee the progress of various components. In support of the program, here are the data resources and synthesis reports.
- List of the non-attainment cities and designated airsheds (here)
- A review of the approved action plans (here)
- Download ambient monitoring needs information by airshed (here)
- Download GIS road lines and road density information by airshed (here)
- Download GIS urban built-up area files by airshed (here)
- Download average TROPOMI extracts for the designated airsheds for 2019-2023 – NO2, SO2, O3, HCHO
- Download monthly average meteorological data from reanalysis fields for 1980-2023 – 2m-temp, rainfall
- Explore more here
What is Polluting Delhi’s Air?
Air pollution in (urban and rural) India is a growing public concern, and city of Delhi (its capital) is one of the most studied city with a disproportionate share of media attention. Yet, we do not seem to have decisive answers to simple questions like how polluted is the city, what are the main sources, and where to start to control pollution in the city. A review of Delhi’s air quality from 1990 to 2022 from data, sectoral, judicial, and institutional perspectives was published as a journal article in 2023 and the associated data and references is available [here].
Launched in August 2017, the APnA city program is designed to provide a starting point for understanding air pollution in urban agglomerations to support public dialogue and policy discussions. Architecture behind the APnA city program is carved and updated from our operational all India air quality forecasting platform.
We currently have stories for 60 Indian cities – Agra, Amritsar, Bengaluru, Bhopal, Bhubaneswar, Chandigarh-Ambala-Patiala, Chennai, Coimbatore, Dehra Dun, Indore, Jaipur, Kanpur, Kochi, Ludhiana, Nagpur, Patna, Pune, Raipur-Durg-Bhilai, Ranchi, Varanasi, Agartala, Ahmedabad, Allahabad, Asansol-Durgapur, Aurangabad, Dharwad-Hubli, Dhanbad-Bokaro, Gaya, Guwahati-Dispur, Gwalior, Hyderabad, Jamshedpur, Jodhpur, Kolkata-Howrah, Kota, Lucknow, Madurai, Mumbai, Nashik, Panjim-Vasco-Margao, Puducherry, Rajkot, Shimla, Srinagar, Surat, Thiruvananthapuram, Tiruchirapalli, Vadodara, Vijayawada-Guntur, and Visakhapatnam.
Primers for Air Quality Managers
Summary of Air Quality in India between 1998-2020
Reanalyzed PM2.5 concentrations and modelled source contributions were analyzed to present (a) India’s % area exposed to various pollution bins in 1998-2020 (b) India’s % population exposed to various pollution bins in 1998-2020 (c) All India pollution maps for 1998-2020 (d) State and Union Territory maps for 1998-2020 (e) State pollution rank among the 36 States and Union Territories for 1998-2020 and (f) Average % source contributions at State level for 2017. All the maps, extracted data files, infographs, and animations are available here.
Open access journal article “Evolution of India’s PM2.5 Pollution Between 1998 and 2020 Using Global Reanalysis Fields Coupled with Satellite Observations and Fuel Consumption Patterns” and supplementary information is published here.
Air Quality Forecasts for India – State-level Summaries
Our forecasting system also includes a high-resolution medium-range meteorological system for the next 72-hours, processed through 3D-WRF meteorological model and the GFS meteorological fields, followed by chemical transport modeling using the CAMx modeling system and a detailed emissions inventory for anthropogenic and natural sources. The modeling domain covers the Indian subcontinent at a temporal resolution of 1 hour. Air quality information is available as tables, time series, and maps at national and state level. A glimpse of state-level summary of PM2.5 concentrations, source contributions, and meteorological data is below for the state of Uttar Pradesh. For other states and more, click here [main link].
Irrespective of the monitoring approaches and equipment, the initiation process requires an understanding of the pollution loads, mix of sources, and geography of the city to decide how much to monitor for better spatial representation and how many times to monitor for better
temporal representation. In this report, we defined (a) the size of NCAP city airsheds (b) the recommended number of ambient air quality monitoring sites in an airshed (c) the operational sampling frequency to support receptor-based source apportionment studies. These resources are necessary for strengthening the monitoring needs of an airshed to track pollution levels, to conduct receptor-model-based source apportionment studies, and to support long-term air quality management plans.
Here we present a repository of resource links on who is monitoring air quality in India, where is the data stored, how to access the data from the official and global repositories, and an illustrated note on how to interpret air quality data and what we can do. The crux of this repository is about India’s air quality. However, the links also lead to information for worldwide network of resources.
Same primer on air pollution monitoring in Hindi is available here.
Here we present a repository of resource links ranging from official portals; guidelines, acts, and rules documents; compiled statistics, maps, and other geospatial databases; satellite observations and tools; ambient air quality monitoring data from official and unofficial networks; global and regional emission inventories; global reanalysis fields; and global meteorological data fields and visualization portals, necessary for putting together energy, emissions, and air pollution analysis in India.
All the database links are also available as a PDF under the working paper series.
India observed four lockdown phases between March and May 2020: (a) March 24 to April 14 (21 days); (b) April 15 to May 3 (19 days); (c) May 4 to May 17 (14 days); and (d) May 18 to May 31 (14 days). As the lockdown periods were extended, air quality improved at various degrees, not just in the big cities like Delhi, Mumbai, Kolkata, and Chennai, but across the country. We explored the air-quality trends in cities with at least one ambient monitoring station each, for all pollutants responsible for defining India’s official air quality index. The data is available here.
Atmospheric science defines the air pollution problem as (a) a dynamic situation where the air is moving at various speeds with no boundaries and (b) a complex mixture of chemical compounds constantly forming and transforming into other compounds. With no boundaries, it is unscientific to assume that one can trap air, clean it, and release into the same atmosphere simultaneously. Access the paper which describes why the idea of vacuuming outdoor air pollution is unrealistic and some commentary notes.
November, 2017: Two months ago, we released the following infograph [PDF], pointing out that media and public interest in Delhi’s air quality peaks around Diwali, stays up there for a couple of weeks and slowly dies down towards the end of winter. This pattern is consistent with the past years as well. The graph plots “relative interest” in the topic of air pollution as quantified by Google searches. We wrote an accompanying article that expands on this issue in the WIRE. This reference note is an attempt to consolidate what we understand as the extent of fireworks burnt during Diwali 2017 in Delhi, its share in overall air quality during the event, and current role of judiciary in tackling this source. [main link]
Status of Air Monitoring in India
The continuous air monitoring data from all the publicly accessible stations operated and maintained by the Central Pollution Control Board (CPCB) and the State Pollution Control Boards is presented here as an online resource. All the data from these stations is available from CPCB website.
This blog piece explains ways in which this data can be accessed and processed for further applications.
We also present an assessment of what India needs to spatially, temporally, and statistically represent the ambient pollution in the urban and the rural areas – based on thumb rule proposed by CPCB and the district level urban and rural population (as per 2011 census). We estimate a need for 4,000 continuous monitoring stations (2,800 in the urban areas and 1,200 in the rural areas).
This resource link presents the sources of air quality data from official and unofficial portals and some repositories of the data for immediate use.
Open fires associated with agricultural residue clearing (after the seasonal harvests and a typical process to prepare for the next crop) and forest fires (associated with hot and dry conditions and some times intentional) is an important source of particulate and trace gas emissions. Detection of these fires is a complex methodology, made easy with the availability of a series of open satellite feeds. We utilize the NASA Worldview platform to visualize and access this information. Image to the right presents all open fires detected over the Indian Subcontinent in the last 24 hours (updated with VIIRS feed every 3 hours). A multi-pollutant emissions inventory, estimated using the location information and land-use databases (agricultural, forest, urban, water, arid, etc.) is available from UCAR-FINN program. For more details and to access archives, click here.