Every few minutes the air rings out with an explosion as police release another tear gas round. Small fires burn every few hundred meters, and the air smells of tear gas, burning rubber and petrol.

It's tense on Hennessy Road in Causeway Bay, as water cannon vans and lines of riot police make their way down the road. Meanwhile small groups of protesters charge forward throwing petrol bombs and banging poles. It's loud with chants, metal clanging and the sirens of the police vans.

In one heated moment, police fired rounds of tear gas and rubber bullets, and protesters charged and retreated. But the stand-off is back on now, as both sides regroup.