The Asian Development Bank again lowered its growth outlook for developing Asia, penciling in an expansion rate for China at under 6% next year amid its trade dispute with the U.S.

The Philippines-based institution now projects developing Asia's GDP to grow 5.2% in 2019 and 2020, down from its September growth projections of 5.4% and 5.5%, respectively.

Persistent trade tensions between the U.S. and China remain one of the key risks to the region's outlook, according to the report.

The ADB lowered its forecasts for all subregions except Central Asia, whose GDP growth is projected to reach 4.6% in 2019 and 4.5% in 2020, up from an earlier forecast of 4.4% and 4.3%, respectively.

In East Asia, growth is expected at 5.4% and 5.2% for this year and the next, respectively, down from 5.5% and 5.4% previously. China's expansion is expected to moderate to 6.1% in 2019 and 5.8% in 2020 from 6.6% in 2018. The ADB had previously projected China's growth rates at 6.2% for 2019 and 6.0% for 2020.

A trade agreement with the U.S. should push the 2020 Chinese growth rate higher, the ADB said.

The institution also cut its outlook for South Asia, with India's GDP growth estimates slashed to 5.1% from 6.5% for this year, and to 6.5% from 7.2% for 2020.

Meanwhile, the ADB trimmed growth outlook to 4.4% for Southeast Asia for 2019, compared with a prior forecast of 4.5%, while maintaining the 4.7% estimate for 2020.

Growth for the Pacific region was trimmed to 4.0% from 4.2% for 2019 and to 2.5% from 2.6% for 2020.