US President Donald Trump received a rapturous welcome yesterday when he touched down in India — but relations between the two countries haven’t always been so warm. Here are six things to know about US-India relations:

The start of independent ties: India’s first Prime Minister visited the US in 1949, soon after India gained independence from British rule — but relations worsened in the coming decades.

India wasn’t formally aligned to any side during the Cold War, but grew closer to the Soviet Union, which was giving New Delhi economic and military assistance in the 60s.

Chaos in 1971: The 1971 India-Pakistan War led to the creation of Bangladesh, formerly East Pakistan. The US sided with Islamabad, given Pakistan’s role as a mediator for the US with China.

In 1968 India had refused to sign the Nuclear Non-Proliferation Treaty, accusing the US, the Soviet Union and the UK of «atomic collusion.» After the 1971 warfare, India ramped up its nuclear development, and approved plans for the first nuclear test in 1972.

India’s nuclear ambitions damaged US relations: In 1974, India held its first successful underground nuclear test. India maintained the test was for peaceful purposes, but many other countries weren’t convinced, and it led to decades of estrangement with the US.

A new era: US President Bill Clinton visited India in 2000, the first such trip by a US president for more than 20 years. It thawed relations, and the nuclear issue was effectively set aside in 2005, when the two governments signed a framework lifting a US moratorium on nuclear energy trade with India.

The relationship today: The US is now India’s largest trading partner in goods and services combined — but trade tensions have arisen after the US filed a lawsuit in 2018 against India for subsidizing exports.

There’s also the issue of restrictions on H-1B work visas: Trump has repeatedly accused tech companies in the US of using the program to replace Americans with cheaper foreign workers.

The Indian diaspora: There are an estimated four million Indian-origin American citizens, along with a further one million non-resident Indians and more than 200,000 Indian students in the US.

Indians with foreign citizenship cannot vote, but they are among the richest immigrant communities in the US. For Trump, now in an election year, a visit to India could generate backing from the Indian diaspora back in the US.

Read the full story here.