Owners of older diesel trucks and buses may soon get a much cheaper alternative to replacing their vehicles purely to reduce emissions.
TOI reports that the government is preparing to allow retrofit emission-control devices on BS4, BS3 and older diesel commercial vehicles. The device is expected to cost only around Rs 4,000 to Rs 5,000 and, according to testing cited by Road Transport Minister Nitin Gadkari, can cut particulate matter emissions by up to 90 percent and nitrogen oxides by around 60 percent.
Most strikingly, the government says a properly retrofitted older vehicle can bring its emissions broadly on par with BS6 standards. The Road Transport Ministry is expected to notify Automotive Industry Standard 228, or AIS 228, which will set the technical and performance requirements for these retrofit systems.
An emission-control retrofit does not convert an old engine into a BS6 engine. It treats pollutants in the exhaust after combustion, reducing the amount that finally leaves the tailpipe. The technology is based on an IIT Delhi innovation and has completed testing.
The claimed reductions are substantial. Particulate matter is the soot and extremely small particles associated particularly with older diesel exhaust. Nitrogen oxides, usually shortened to NOx, are another major diesel pollutant.
Reducing particulate matter by up to 90 percent and NOx by 60 percent could therefore make a big difference if the devices perform consistently outside a test environment. Even allowing for installation and maintenance requirements that may emerge with the final rules, that is tiny compared with replacing a functioning heavy commercial vehicle.
There is an obvious question for owners of older private diesel cars, particularly in Delhi-NCR. Can the same idea allow a 10-year-old diesel car to remain on the road? Nothing announced so far says that it can.
The current proposal specifically concerns older diesel trucks and buses. It does not overturn Delhi-NCR’s age-based restrictions on private diesel cars, nor does it create a legal exemption for a private car fitted with an emission-control device.
A commercial truck can cover far more kilometres than a typical private car, so allowing a low-cost retrofit on high-use commercial vehicles while age restrictions continue for private cars will inevitably raise questions.
The government is not abandoning its vehicle-scrappage policy. Gadkari presented retrofitting as complementary to replacing ageing heavy vehicles, not as a substitute for scrapping every old truck or bus.
A mechanically sound older bus that can meet much tighter tailpipe limits after a low-cost retrofit may still have useful life remaining. A badly maintained or structurally worn vehicle may be better replaced regardless of what comes out of its exhaust.
The final AIS 228 rules will need to address certification, approved manufacturers, correct fitment and how the system’s performance is checked over time. An emission device that works when new but is later removed, blocked, poorly maintained or replaced with a non-compliant part solves little.
Still, the basic proposition is unusually attractive: spend roughly Rs 5,000 on an older diesel truck or bus and potentially cut soot by up to 90 percent and NOx by 60 percent. If those numbers survive everyday operation, retrofitting could reduce pollution from existing fleets far faster and more cheaply than waiting for every old commercial vehicle to be replaced.
The next important document is AIS 228 itself. That will tell operators exactly which vehicles qualify, which devices can legally be fitted and what testing will be required to prove that an old diesel really is running at BS6-like emission levels.