Crackers Pollute for 5 Days, Parali for 15, Vehicles for 365

 Crackers Pollute for 5 Days, Parali for 15, Vehicles for 365: Time for ROTE

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Respected Shri Nitin Gadkariji,

Union Minister for Road Transport and Highways

This Deepavali, despite the Supreme Court's restrictions, Delhi's air touched 50

times the WHO limit in some areas. The usual blame falls on firecrackers and

parali burning.

But consider this:

• Firecrackers pollute Delhi's air for about 5 days

• Parali burning pollutes it for about 15 days

• Vehicles pollute it for 365 days a year

The Government's own data agrees. CAQM's source apportionment shows vehicles

contribute about 23% of Delhi's PM2.5 in winter and 19% in summer, and nearly

half of all local emissions during peak episodes. Even this year, with stubble fires

sharply down, PM2.5 stayed far above safe levels because of traffic and other local

sources.

This is precisely the problem my ROTE ( Reduction of Transport Emissions )

 framework, Harm Quotient → Trans-Score → Trans-Tax, was designed to solve, as 

I had written to you earlier in August.

Sir, I now wish to submit one important refinement.

THE HIDDEN SHARE: NOx

About 27% of Delhi's winter PM2.5 is "secondary" particulate matter, formed in the

air from gases such as NOx, of which vehicles are the largest source. If Harm

Quotient counts only tailpipe particulates, it under-states a vehicle's true harm. I

therefore propose that Harm Quotient explicitly include NOx, as set out in the

Annexure below.

Two further suggestions:

1. Delhi-NCR pilot: Since much of Delhi's pollution comes from the surrounding

 NCR, a ROTE pilot covering the entire Delhi-NCR airshed, alongside the proposed

 Chennai pilot, would deliver the most visible results

2. Priority segments: Weight Trans-Scores towards two-wheelers and heavy

 commercial vehicles, which dominate on-road transport emissions, with EV-switch

 credits rather than penalties alone

With the AIS-189/AIS-190 rules already mandating secure vehicle-cloud data

exchange from 1 October 2026, the infrastructure to measure Harm Quotient is

arriving in every new vehicle. The policy to use it can follow.

With regards,

Hemen Parekh

www.HemenParekh.ai

Mumbai

9 Nov 2026

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ANNEXURE: NOx-WEIGHTED HARM QUOTIENT

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A. Formula (per km)

HQ  

= [ PM + (k × NOx) ] × W(age) × W(capacity) × W(location) × W(time) ×

    W(driving)

where

• PM = particulate emission, g/km (from energy source and emission norm)

• NOx = NOx emission, g/km

• k = NOx-to-PM2.5 conversion factor (illustrative 0.25; to be calibrated by IIT

   Madras / IITM using the Decision Support System)

• The result is expressed as grams of "PM2.5-equivalent" per km

B. Illustrative weights (to be calibrated in the pilot)

• W(age): 

0–5 yrs = 1.0 | 5–10 yrs = 1.2 | over 10 yrs = 1.5

• W(capacity): 

divided by average occupancy or load, so a full bus scores far lower per person than a single-occupant car

• W(location): 

non-attainment airsheds such as Delhi-NCR = 1.5 | others = 1.0

• W(time): 

winter months (Oct–Feb) and rush hours = 1.3 | otherwise = 1.0

• W(driving): 

heavy idling / congestion = 1.2 | free-flowing = 1.0

C. Worked example (emission-norm limits for passenger cars, k = 0.25, all W = 1.0)

• BS-IV diesel car: 0.025 + (0.25 × 0.25) = 0.088 g/km

• BS-VI diesel car: 0.0045 + (0.25 × 0.08) = 0.025 g/km

• BS-VI petrol car: 0.0045 + (0.25 × 0.06) = 0.020 g/km

• Electric car: 0 g/km (tailpipe)

For the BS-IV diesel car, NOx accounts for about 70% of its Harm Quotient. A PM-only formula would miss most of its harm.

The same BS-IV diesel car, over 10 years old, driven in Delhi-NCR during winter: 0.088 × 1.5 × 1.5 × 1.3 = 0.26 g/km, about 13 times a new BS-VI petrol car on a normal day.

D. Link to Trans-Score

Trans-Score = 100 × [ 1 − (monthly average HQ ÷ reference ceiling HQ) ], limited to 0–100

Trans-Tax bands remain unchanged: Trans-Score of 75 and above earns a credit, 25 and below attracts a penalty, 26–74 is neutral.