Asia-Pacific markets traded mixed Monday as investors assess China's RatingDog manufacturing data for August. The metric - which was previously known as the Caixin Purchasing Managers' Index - came in at 50.5, compared to a contraction of 49.5 the month before.

Data released Sunday showed that the country's manufacturing PMI data came in at 49.4 in August, compared to 49.3 the month before.

Investors are also assessing the developments in India and China relations, after leaders from both countries agreed that they are development partners, not rivals during a two-day meeting of the Shanghai Cooperation Organization regional security bloc. Chinese President Xi Jinping is expected to deliver a speech at the summit.

Hong Kong's Hang Seng index rose 1.9%, while mainland China's CSI 300 was flat.

In Japan, the Nikkei 225 declined by 1.83%. Losses were led by Advantest which plunged 8.65%, Disco Corp which declined 8.51% and SoftBank Group which dropped by 6.01%.

Meanwhile, Japan's broader Topix index lost 0.68%.

Over in South Korea, the Kospi index fell 0.4%, while the small-cap Kosdaq lost 0.57%.

Australia's S&P/ASX 200 benchmark retreated 0.55%.

Investors were also assessing a U.S. federal appeals court ruling that most of U.S. President Donald Trump's "reciprocal tariffs are illegal."

The U.S. Court of Appeals for the Federal Circuit held Friday ruled that Trump had overstepped his presidential authority by imposing levies on virtually every country in the world as part of his April 2 "liberation day" announcement.

Source: CNBC