All the CNG vehicle owners have been asked to use certified CNG cylinders and kit in their vehicles and get them tested from a trained personnel after every five years. A spokesman of Oil and Gas Regulator Authority (OGRA) also advised the owners to get their vehicle's CNG system inspected at least once in a year from a trained personnel. He said the Compressed Natural Gas (CNG) is a high-pressure gas for which specially designed and fabricated seamless cylinders manufactured in accordance with prescribed standard should be used in vehicles.