Special Issue on Air Pollution and its Impact in South and Southeast Asia (II)

Shubham Sharma1, Mukesh Khare1, Sri Harsha Kota  1,2  

1 Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
2 Arun Duggal Centre of Excellence for Research in Climate Change and Air Pollution (CERCA), IIT Delhi, New Delhi 110016, India

Received: December 9, 2021
Revised: March 29, 2022
Accepted: April 23, 2022

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.210377  

Cite this article:

Sharma, S., Khare, M., Kota, S.H. (2022). Action Plans to Reduce PM2.5 Concentrations in Hotspots of Delhi-NCR Using a One-way Coupled Modeling Approach. Aerosol Air Qual. Res. 22, 210377. https://doi.org/10.4209/aaqr.210377


  • Source-specific interventions were effective in addressing high PM2.5 scenarios.
  • Reducing total emissions citywide by 20% resulted in ~15% reduction in PM2.5.
  • PM2.5 decreased by ~24% by implementing hotspot-specific and citywide interventions.
  • Non-local emissions influence the efficacy of hotspot-specific interventions.
  • Addressing compliance complaints alone can lead to a 12.16% reduction of PM2.5.


The concentration of PM2.5 in Delhi, one of the most polluted capital cities globally, frequently exceeds the Indian National Ambient Air Quality Standards, especially during the post-monsoon and winter months. This study evaluates the changes in PM2.5 concentrations across Delhi using a one way coupled model (WRF-CMAQ-AERMOD) for various hotspot-specific intervention scenarios during post-monsoon and winter of 2018. PM2.5 concentrations reduced up to 15% by scaling down total emissions across Delhi by 20%. An additional 9% reduction across entire Delhi and ~28% reduction at the top ten observation-based hotspots could be achieved if emissions of industry, unpaved road dust and construction in selected emission hotspots are made zero. Non-local contribution in hotspots of the city varied significantly. For example, the difference in the reductions of PM2.5 concentrations from citywide versus hotspot-specific interventions is estimated to be 28% at DU North Campus and 11% at Anand Vihar. An average reduction of 12% was computed when construction and MSW burning emissions were down sized 100% in the locations identified based on compliance complaints received at the Central Pollution Control Board’s online complaint portal. A marginal reduction of 4% estimated for the previously implemented traffic rationing measure, the odd-even rule, indicates that such regulation of vehicles alone might be inefficacious. The results suggest that stakeholders must focus on—(a) source and hotspot-specific interventions alongside city wide interventions to significantly reduce ambient PM2.5 concentrations, (b) local and non-local contributions from regions outside the hotspot grid needs to be carefully considered for estimating efficacy of an action plan.

Keywords: PM2.5, WRF-CMAQ-AERMOD, Delhi, Intervention scenarios, Hotspot

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Special Call for Papers Air Pollution and its impact in South and Southeast Asia

2020 Impact Factor: 3.063
5-Year Impact Factor: 2.857

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