The Moody's Investor Service report also cut India's gross domestic product (GDP) growth rate for 2020 by a similar 0.6 percentage points to 6.7 per cent.
"The moderation in business sentiment and slow flow of credit to corporates have contributed to weaker investment in India," a Moody's release said.
A weaker global economy has stunted Asian exports and the uncertain operating environment has weighed on investment, according to the ratings multinational.
The report said externally oriented economies in the region saw a sharper slowing during the first six months of 2019, while domestic factors have had a greater influence on growth in India, Japan and the Philippines.
Of the 16 economies surveyed, Hong Kong and Singapore have shown particularly weak expansion this year, with very large deteriorations in real GDP growth when compared to the first half of 2018.
"In particular, softer capital formation has mirrored the weakening in exports, especially for trade-reliant economies such as Korea and Hong Kong," it said.
In Malaysia and Sri Lanka, fiscal tightening has acted as a drag on growth.
The Amereican agency also said the slower overall GDP growth in the region has not yet weighed significantly on the broader employment situation, while generally benign inflationary conditions have supported purchasing power across Asia-Pacific.
The report covers Australia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Mongolia, New Zealand, the Philippines, Singapore, Sri Lanka, Taiwan, Thailand and Vietnam.
( With inputs from IANS )