Explainer: Beijing questions Hong Kong mask ruling

A Chinese parliamentary body has questioned a Hong Kong court's decision to overturn a ban on face masks - in a move likely to raise concerns over Hong Kong's legal independence, and increase anger on its streets.

The mask ban was brought in by Hong Kong leader Carrie Lam at the start of October though, despite the risk of arrest, masks have continued to be a feature on Hong Kong's streets over the six weeks that followed.

On Monday (November 18), Hong Kong's High Court ruled the ban "excessive" and "unconstitutional" under the Basic Law, the documents that outline the extent of Hong Kong's freedoms and autonomy.

But the next day, China's official Xinhua news agency reported a statement from the legislative affairs commission of the Standing Committee of the National People's Congress - put simply, that's Beijing's top lawmaking body.

It said Hong Kong's courts had no power to rule on the constitutionality of the city's laws.

Not everyone agrees; the Hong Kong Bar Association, for example, says Beijing's statement is "legally incorrect".

Some experts in Hong Kong and beyond say precedents set by Hong Kong's highest court, the Court of Final Appeal, make it clear that the city's courts do have the power to declare local legislation unconstitutional.

But, they acknowledge, the Basic Law gives the NPC Standing Committee the ultimate power of reinterpretation.

That power has been sparingly used so far - a reflection of the delicate balance between Hong Kong's British-based legal traditions and Beijing's Communist Party leadership.

But the situation has put Hong Kong's government in a tight spot.

It's widely expected to appeal the High Court's decision to overturn the ban which could end up bringing the case to the Final Court of Appeal.

That could bring pressure on Beijing to step in and reinterpret rulings in the case - effectively limiting the power of Hong Kong's courts.

Such action would likely add to local perceptions that Hong Kong's freedoms and autonomy are being eroded.