Technologies introduced to clean/scrub/recover the emissions are now know as "end of pipe" technologies. They are expensive and a wasteful way to deal with pollution. "Cleaner technologies" advocate going back to the source - as industrial hygiene intended. At source the environmental aspects of a process can be dealt with before they become environmental impacts.

Visit United Nations for relevant case studies http://www.emcentre.com /unepweb/startfiles/index_r02_c7.jpg

The key difference between pollution control and cleaner production is timing. Pollution control is after-the-event, a 'react and treat' approach. Cleaner production is a forward-looking, 'anticipate and prevent' philosophy.