Are anti-smog guns the right choice for reducing Delhi’s dust during winters?

An exploration of Delhi’s dust-control plans and the need for smarter, scalable interventions.

For the first time, Delhi has a comprehensive Air Pollution Mitigation Plan for 2025 that outlines a wide range of strategies across sectors. Among these measures is a set of actions focused on managing road dust and resuspension. The plan recommends using sprinklers, portable anti-smog guns, and mechanical road sweepers to reduce resuspended dust, particularly PM10. 

Among dust mitigation technologies, there is limited evidence on the effectiveness of the anti-smog gun (ASG) technology. These guns spray fine, nebulised water in the form of mist through high-pressure propellers into the air, creating a rain-like effect. This process increases the mass of suspended air particles, causing them to settle down. It is similar to how rainfall brings down pollutants and clears the sky, but in this case is limited only to the area where water is sprayed. Here, we discuss whether anti-smog guns are effective in Delhi winters, given their high operational and maintenance cost.

There are two types of anti-smog guns: those equipped with coarse nozzles, which are typically used at construction sites, and those with finer nozzles, which are more effective for controlling airborne particles in urban areas. In urban anti-smog guns, water is utilised at a rate of 40 to 250 litres per minute and has a throw distance range between 30–100m, covering an area of 27000–31000 sq.m.

During the winter months, when the ASGs would primarily be in use, road dust accounts for about 15 per cent of ambient PM2.5. However, the recent report on the National Clean Air Programme (NCAP) spending shows that around 64 per cent of the available funds are allocated to road dust mitigation. Recently, Delhi has also invested around INR 13.53 Cr. in road dust-related measures, much of which goes towards procuring technologies like ASGs, mechanical sweepers, etc. Given their high operational and maintenance costs, these measures must undergo rigorous scientific evaluation, particularly in view of the ongoing focus on dust control.

On 29th May of this year, the Delhi government’s Department of Environment and Forests passed administrative orders that mandated the installation of anti-smog guns on high-rise buildings—commercial complexes, malls, hotels, office buildings, and educational institutions—with a height of G+5 floors and above or exceeding a built area of 3,000 sq.m. It is important to highlight some key aspects of these orders. Anti-smog guns are intended to “suppress dust, which is the dominant source of air pollution in Delhi.” It further states that “the use of anti-smog guns has been recognised as an effective measure for suppressing airborne dust and particulate matter,” and that large-scale replication of such systems “could have a favourable impact on air quality.” It also emphasises that “anti-smog guns thus play a feasible role in managing localised air pollution.” However, while anti-smog guns could be one of the several measures the city needs to reduce air pollution, these should not be the primary choice.

What does the CEEW analysis reveal about ASG installations in Delhi?

The Council on Energy, Environment and Water (CEEW) evaluated the potential number of facilities and costs associated with the deployment of anti-smog guns and other such devices at the scale envisioned in the May order. This preliminary analysis could be considered alongside scientific evidence on the efficacy of these interventions before mandating large-scale implementation.

Based on our analysis, there are ~58,505 buildings (both residential and commercial) across New Delhi. Applying filters based on building classification (as per the draft master plan) and height (G+5 and above), 452 buildings qualified as high-rises under the directive. Based on the guidelines issued for the specific numbers of anti-smog guns to be installed, we identified at least 84 to have a built-up area of 3,000 sq.m. or more. However, this number likely represents a lower bound, as some premises may collectively exceed the 3,000 sq. m threshold but are registered as individual buildings, creating uncertainty about how the directive’s criteria apply.

The building clusters and their coverage highlight major spatial gaps

• More than 50 per cent of these buildings are clustered around South and Central Delhi. A spatial analysis of the 452 buildings reveals that around 230 are concentrated in these two zones. The top three wards with the most number of high-rises are Malviya Nagar (76), Greater Kailash-I (47), and Daryaganj (43).
  
• Only two per cent of Delhi's roads are covered by the deployment of anti-smog guns. Further, a 50-metre buffer around identified high-rise buildings only amounts to a total area of around 3–7 sq. km, out of Delhi's total area (1,487 sq. km).
  
• Areas with high PM10 have been overlooked. Anti-smog guns could help manage localised dust resuspensions, but their usefulness depends on whether they are deployed in areas with he highest dust loads. Although PM2.5 levels remain fairly uniform across Delhi, areas such as Jahangirpuri, Wazirpur, and Mundka often record higher PM10 concentrations due to broken roads, construction and dust (C&D) dumps and road dust, particularly in winter or even year-round. This underscores the need to prioritise dust hotspots for any such deployment and to conduct impact assessments to understand how effective these measures actually are.

What other challenges await the implementation of the anti-smog gun mandate?

Beyond coverage and efficacy, the anti-smog gun mandate could also face several on-ground challenges:

• The capital investment required is significant. With unit costs averaging around INR 1.5–2.5 lakhs per anti-smog gun (varies with the throw range), large buildings will need multiple installations. We estimate that 250–600 anti-smog guns may need to be installed in these buildings, requiring an investment of around INR 5–12 crore. Additionally, monthly electricity costs for these guns could range from INR ~15,000–18,000 per ASG per month and are likely to be borne by the occupants. 
  The throw range of a typical ASG is between 30 metres and 50 metres, though this can increase with engine capacity. The latest mandate suggests a horizontal throw distance of 75–100 metres, raising both upfront and operational expenses.
• Daily operations pose major logistical challenges to the water supply. Deploying these 250–600 anti-smog guns would require nearly 25–90 lakh litres of water per day, excluding losses from leaks and spills. In a city already grappling with water shortages, such a measure becomes operationally unsustainable. Moreover, existing guidelines discourage the use of primary or secondary treated used water, considering only Class A or B water—fit for drinking (post-disinfection) or outdoor bathing—as acceptable. As a result, unless the water undergoes tertiary treatment and meets the prescribed quality standard, spraying it in public areas may reintroduce other pollutants and pathogens into the air, undermining the very goal of the intervention.
• Many existing buildings may not be structurally equipped to support such installations. While no systematic assessments have been carried out, several buildings are likely to lack the rooftop load capacity, access, or clearance needed for safe deployment. Older structures may require costly retrofitting, raising safety concerns, particularly during high wind speeds. In multi-tenant buildings, unclear ownership of rooftop space and cost-sharing disputes further complicate implementation and long-term maintenance.

How can Delhi build a robust and effective dust pollution mitigation system?

To ensure that dust-control technologies deliver cost-effective results, Delhi should adopt a transparent and standardised evaluation framework of these available technologies. The framework could include the following criteria:

• Operational costs: Considering not only the upfront capital expenditure but also the full range of ongoing costs—maintenance, repairs, manpower, consumables, energy use, and the frequency with which parts need replacement. Capital costs should be amortised over the realistic life span of the technology, allowing policymakers to compare options on a “cost per year” and “cost per unit of PM2.5 reduced” basis. The aim is to identify technologies that remain affordable to operate at scale, not just to procure.
• PM reduction efficiency: Evaluation should estimate the total reduction over the full operational life of the technology. This must be based on realistic assumptions: expected hours of operation, geographical or site coverage, the intensity of dust sources in that area, and the proven efficiency of the technology under Indian conditions. Interventions that consistently deliver higher cumulative reductions should be prioritised over solutions that provide only marginal or short-term benefits.
• Logistical operational and monitoring challenges: Assessment should consider the practical logistical issues that affect how reliability and scalability of a technology to be deployed and monitored. This includes installation complexity; difficulty of routine inspections; the need for digital tracking infrastructure; dependency on skilled operators; and the likelihood of operational downtime. 

Technologies with simpler, more robust operational requirements—and lower risk of misuse or neglect—should be favoured. Monitoring systems and institutional accountability reforms also remain important enablers but should be assessed separately, as they are not pollution-mitigation technologies themselves. The priority for technology deployment should be clear: invest in solutions that deliver the greatest and most reliable PM2.5 reductions per unit cost with minimal operational friction.

Delhi’s commitment to cleaner air is commendable, but real impact demands targeted, optimised, and evidence-based solutions. Unless the city strikes a balance between intent, impact, infrastructure, and institutional readiness, these measures risk falling short or even exacerbating other challenges. Prioritising long-term investments and accountability will ensure that pollution control efforts are not just visible but also effective.

Arpan Patra is a Programme Associate, Mohammed Sahbaz Ahmed is a Research Analyst, and Karthik Ganesan is a Fellow and Director, Strategic Partnerships at the Council on Energy, Environment and Water (CEEW).

Arpan PatraAuthor

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