A recent study, part of The Real Urban Emissions (TRUE) Initiative, has shown that actual emissions from vehicles on Delhi and Gurugram roads far exceed those recorded in laboratory tests. Using remote sensing technology, the study, conducted in partnership with local authorities, found that nitrogen oxide (NOx) emissions from BS-VI vehicles are significantly lower than from older BS-IV vehicles. BS-VI private cars emit 81% less NOx than BS-IV models, while BS-VI buses produce 95% less NOx compared to their BS-IV counterparts. However, the study also challenges the common perception of compressed natural gas (CNG) as a cleaner fuel. It revealed that CNG-powered vehicles, including taxis and light goods vehicles, emit high levels of NOx— up to 14.2 times the NOx limit for some models, while taxis exceed their limits by four times. This indicates that real-world emissions are crucial for improving air quality, rather than relying solely on lab tests. The findings come as the Supreme Court pushes for the implementation of Automotive Industry Standard (AIS) 170, which will standardise remote sensing equipment to measure vehicle emissions.