The phrase “Process Pigging” took me completely by surprise. I dug up some material to understand the process.
System pigging is a cleaning process using a plug introduced into the system pipe and launched using some high pressure means. The plug moves through the system including bends. It will carry off dirt and scales from the pipe internal walls as it is propelled forward.
Please go to the three linked pages to understand more. It is not known whether the equipment and plugs are available in India, but the process seems to be interesting in some of the application such as fire main pipe, compressed air pipes, fuel pipes, etc.