Mohtaram @sohail009 Sahib,
This is why CNG cylinders explode. It is just simple Physics. Just take a Coca Cola can and make it airtight. Then find an air-pump and start filling it up with air making sure about two things; Firstly, stay at a safe distance of about 50 metres wearing protective gear like a helmet and safety goggles and secondly make sure the system is airtight. When high pressures inside the Coca Cola can will reach a level above the can can withstand, it (the can) will explode because the tin of the Coca Cola can is weak and can't withstand high pressure.
Same goes for substandard CNG cylinders. If they are not made of good solid material then they will explode if you fill them up with high pressure CNG. It is quite sad that the government has banned the import of new CNG kits and cylinders into the country and still making its people suffer in long queues to fill up their cars with CNG.
Sub say dukh bharee baat yay hay kay koi nizaam nahin hamaray mulk ka aur koi poochnay waala nahin. What people do? They make do with substandard uncertified welded cylinders which explode after being filled up with high pressure causing serious loss of life.
There is a CNG Mafia working in the country which came into existence in the 1980s at the time of the government of General Zia when one guy working in OGDC introduced the Lovato CNG kits from Italy. A selected company was given licence to import them so that millions of rupees could be made and it was split between the corrupt bureaucracy and the importer who was given the licence. This Mafia made a lot of money by doing this immoral business.
Some technocrats at that time blew the whistle because they understood what was going to happen. They said that it was not in the interest of the country to switch cars to CNG because by doing so a day would come when there would not be any gas for the kitchen, domestic heating, industry and electricity generation. This Mafia made sure that those whistle blowers not be heard and today we are facing such a situation.
In Pakistan, 65% of the vehicles are fueled by CNG making it to the top of the list in the world. The second country after Pakistan is Iran with around 21% of its vehicles running on CNG.
A few months from now a new scandal will unfold: The LPG scandal where billions more will be embezzled.
Thanks and regards.