A study conducted by the Centre for Science and Environment has revealed that fuel adulteration in the city goes undetected because detection methods and standards are too weak. Acting on a Supreme Court order, the Environmental Pollution (Prevention and Control) Authority asked the Centre for Science and Environment to undertake an independent inspection of fuel adulteration in Delhi and National Capital region. The study revealed that tests have not been designed to catch adulteration but to test compliance with fuel quality standards. Moreover, a big variation in the sulphur levels in fuels from the refinery to the retail end was discovered.