The largest national flag at Rajiv Chowk on March 7, 2014 in New Delhi, India.

Economic growth in India has slowed down significantly this year — but the third-largest economy in Asia should stage a rebound in 2020 as global conditions are set to improve, according to Goldman Sachs.

That said, the extent of the recovery will likely be modest instead of returning India to the growth rates seen a few years back, said Jan Hatzius, the investment bank's chief economist and head of global economics and markets research.

"As we go into 2020, we think there's a tentative sense of stabilization in the Indian economy," Hatzius told CNBC's "Street Signs Asia" on Tuesday.

India on Friday said its economy grew by 4.5% in the three months to September from the same period a year ago — the slowest growth rate in six years. Goldman Sachs, in a report last week, projected India's growth to fall to 5.1% this year from roughly 7% annually in 2017 and 2018.

The bank forecast the country's growth to pick up to 6.4% next year, according to the report.

An improving global economy and domestic policies such as corporate tax cuts should help to lift economic activity in India, said Hatzius. He added that some economic indicators in the country, such as the manufacturing Purchasing Managers' Index, have improved.

In addition, the country's central bank, the Reserve Bank of India, "probably isn't quite done" with easing monetary policy yet — which is also likely beneficial to growth, he said.

"We'll see how strong the rebound is. We did see a significant deceleration, will it be able to make that up in 2020 and 2021 to get back to the growth rates that we saw a couple years ago?" asked Hatzius.

"That may be a tall order, but incrementally we do think that growth probably picks up somewhat from here," he said.