Why? Because any trip to the main city of Punjab state would have to include a visit to the breathtaking Sikh Golden Temple, where head coverings are mandatory.
Obama is a Christian, but he has regularly had to fight off accusations he is secretly a Muslim; a Pew Forum on Religion and Public Life poll in April found that nearly 1 in 5 Americans believe he is Muslim.
But in India, there are differing reports on the baseball cap issue. Golden Temple authorities insist on a tie-up head covering, while ordinary Sikhs and community leaders have said they have no problem with a baseball cap or a hat. In fact, Sikhs are appealing to the White House to reinstate the Golden Temple on the president's itinerary, and say that it is OK for him to wear casual head gear.
Sikhs had hoped a visit to their nerve center would raise awareness about their religion and the fact that it is completely separate to Islam, even though Punjab shares a long border with Pakistan.
The Sikh religion – concentrated in Punjab – requires that adherents never cut their hair. Most Sikh men twirl their locks under an elaborate decorative turban each morning, in a process that takes up to 15 minutes.
Sikhism is, at its heart, a way of life more than a religion, and stresses good deeds in day-to-day life over what it sees as empty religious rituals.