Too many chinks in Delhi pollution fight: CAG

The three major red flags that the Comptroller and Auditor General (CAG) report found about why vehicles are a major source of pollution in Delhi

The Comptroller and Auditor General’s (CAG) report on Delhi’s air pollution exposed severe lapses in the city’s efforts to mitigate vehicular pollution, highlighting a lack of data on the number of vehicles and their emissions, delays in public transport expansion plans and improper placement of air quality monitors, according to officials familiar with the findings of the agency.

A traffic jam in Mayur Vihar on Friday. (PTI)

To be sure, the report – Prevention and Mitigation of Vehicular Air Pollution in Delhi, prepared in 2022 – is one of the 14 such filings prepared by CAG between 2017 and 2024 that were to be tabled in the Delhi assembly, but were not done so.

The report on pollution also highlighted systemic flaws in the city’s Pollution Under Control (PUC) certification process. It reportedly flagged that vehicles were often certified without testing, and many were passed despite exceeding pollution limits. The fitness certification system for commercial vehicles was described as “dysfunctional” and “prone to misuse,” according to officials who have seen the report. It also highlighted that the city’s 2019 parking rules still remained largely unenforced.

HT’s requests for comments to the Aam Aadmi Party (AAP) did not elicit a response till the time of going to print.

Lack of data about vehicles on the road

A key concern raised in the audit, according to the officials, is the absence of reliable data on the number of vehicles on Delhi’s roads and their emissions. Despite vehicular pollution being one of the primary contributors to the city’s toxic air, no comprehensive assessment of emission load has been conducted, the report said, according to officials who have assessed the report in details.

It also pointed out that neither the transport department nor the environment department had any official records regarding the exact number and type of vehicles operating in Delhi or their pollution output.

Lack of public transport augmentation

Another critical issue raised in the audit was the failure to expand public transport. Despite a growing population and worsening congestion, Delhi’s bus fleet has remained stagnant for years, it allegedly found. The city had only 6,750 buses — both Delhi Transport Corporation (DTC) and cluster — available in March 2021, against a required 11,000.

Shockingly, no new buses were added between 2011 and 2021, even as the number of two-wheelers surged from 43 lakh in 2011 to 81 lakh in 2021. The total number of registered vehicles increased from 69 lakh to 1.3 crore over the same period.

The audit found that Delhi’s transport network was struggling to meet demand. Of the 657 notified bus routes, 238—36% of the total—were not covered at all due to the bus shortage. Additionally, last-mile connectivity remained a persistent problem. While the population grew by 17% between 2011 and 2021, the number of registered Gramin Sewa vehicles, a key mode of last-mile transport, remained stuck at 6,153. These vehicles were also more than a decade old, raising concerns about their fuel efficiency and pollution levels.

The report noted that despite these deficiencies, the Delhi government failed to implement alternative transport solutions such as Monorail, Light Rail Transit, or Electronic Trolley Buses. Although budget provisions had been made for these projects for the past seven years, no concrete steps were taken to execute them.

Irregularities at PUC centres

The officials cited above said that the audit found severe flaws in the city’s Pollution Under Control (PUC) certification system. PUC centres frequently issued certificates without conducting proper tests, it said, allowing high-emission vehicles to continue operating.

Data analysed in the report allegedly revealed that 24% of the 2.21 million diesel vehicles tested between 2015 and 2020 had no recorded emission values. In over 4,000 cases, vehicles exceeding pollution limits were still declared “pass.”

In nearly 7,700 instances, multiple vehicles were tested simultaneously at the same centre, raising concerns about fraudulent certifications. Another 76,865 cases involved certificates being issued within one minute—an impossible timeframe for a legitimate emissions test.

The report also heavily criticised the city’s fitness certification system for commercial vehicles, calling it “dysfunctional” and “prone to misuse.”

Despite having an automated Vehicle Inspection Unit (VIU) at Jhuljhuli, 91-95% of fitness tests were still conducted manually at Burari, where “only visual inspections” were performed. The audit reportedly found cases where vehicles were passed without undergoing any emission test at all.

Moreover, the official said that despite a shortfall of 20-64% in the number of vehicles turning up for mandatory fitness tests, the transport department had no system to remind owners to renew their certificates.

The official said that CAG also pointed out that modern technology for checking vehicular pollution through remote sensing devices was also not adopted, even though it was under consideration from 2009 and the matter had been emphasised by the Supreme Court.

It also flagged concerns over vehicles entering Delhi from neighbouring states, noting that pollution checks were being conducted at only seven out of the city’s 128 entry points. This lack of enforcement meant that high-emission vehicles from other regions were entering the city unchecked.

Enforcement of end-of-life vehicles

The CAG report, according to the official, found that enforcement of end-of-life vehicles (ELVs) regulations was severely lacking.

Despite the National Green Tribunal’s (NGT) directives, only 6.27% of ELVs were deregistered between 2018 and 2021. Of the more than 4.1 million ELVs in Delhi, only 357 were impounded, it flagged. Even vehicles caught visibly polluting were allowed to continue operating as there was insufficient space to store impounded vehicles. Since 2023, the transport department has deregistered over six million ELVs and impounded 10,000 such vehicles, but enforcement remains inadequate, officials said the report highlighted.

Grap and odd-even

The officials cited above said that the audit report also criticised the implementation of the Graded Response Action Plan (Grap), an emergency-based pollution control strategy introduced in 2017. Grap mandates various measures, including the odd-even vehicle rationing scheme, when pollution levels reach critical levels. However, the audit found that these measures were implemented inconsistently.

Between January 2017 and March 2020, pollution levels crossed Grap thresholds 95 times, according to the officials, but the odd-even scheme was enforced only five times, and truck-entry bans were imposed only eight times.

The odd-even scheme, meant to limit vehicles on roads, was undermined by excessive exemptions.

The CAG audit also reportedly found that two-wheelers were excluded from the scheme every time it was implemented, without expert consultation. This effectively meant that 7.56 million vehicles — roughly 66% of Delhi’s fleet — were not covered under the restrictions, significantly weakening its impact. When questioned, the transport department justified the exemptions by citing an inadequate public transport system.

Questions about monitoring stations

Another critical issue raised in the report, officials said, was the improper placement of Delhi’s continuous ambient air quality monitoring stations (CAAQMS), which collect pollution data used to calculate the city’s daily air quality index (AQI). The audit found that 13 of the 24 monitoring stations operated by the Delhi Pollution Control Committee (DPCC) were not located as per Central Pollution Control Board (CPCB) guidelines. These stations were either too close to trees, roads, high-rise buildings, or unpaved surfaces, which could distort readings. Stations at Anand Vihar and Wazirpur, for instance, were near major roads, while those at Civil Lines and Okhla were close to construction sites.

The audit raised concerns that incorrect placement of these stations could lead to unreliable pollution data, ultimately affecting air quality assessments and mitigation policies. In addition, data from these stations was often incomplete — records showed that readings were available for less than 16 hours a day on multiple occasions between 2019 and 2020. Moreover, lead, a toxic metal and key AQI pollutant, was not being measured at any of the 24 DPCC stations.

Another major oversight flagged by the audit was the lack of benzene monitoring at fuel stations. Benzene, a hazardous pollutant released during fuel dispensing, is known to pose serious health risks. The 2017 Comprehensive Action Plan (CAP) mandated the installation of vapour recovery systems (VRS) at all fuel outlets to curb benzene emissions. However, the audit found that these systems were not installed, and benzene levels frequently exceeded permissible limits. Between January 2018 and March 2021, benzene levels were above safe limits 26.94% of the time.