The majority of the problem lies not with pollution created in Hong Kong, but our neighbor to the north. The smoggy skies are a result of the factories in southern Guangdong. You might say it is their fault, but most of the factories are run by HK and Taiwanese companies, and most of the goods are bought overseas in the First World. However, pollution controls in the mainland are very weak. The mainland has to clean its act up too, but the problem lies with everyone.
Unfortunately, relying on factory owners to clean up of their own free will and accord never works. The government will have to force all of them to stop; and they can't just talk about stopping it and then wink at everyone who keeps doing it.