Local traders have welcomed the opening of the pass

The Himalayan pass of Nathu La, 4,000m (14,000 feet) above sea level, was once part of the ancient Silk Road and saw clashes between the sides in the 1960s.

The opening ceremony took place at the windswept border between the Indian state of Sikkim and Tibet.

Nathu La has opened just a few days after the first train service was launched from eastern China to Tibet.

The pass was given a festive look with Chinese and Indian flags fluttering and military bands playing.

China's ambassador to India and local officials from Sikkim and Tibet attended the opening ceremony at the border post in driving rain and bitter cold.

But the BBC's Subir Bhaumik, who was at the opening, says despite the poor weather conditions there was no shortage of enthusiasm among the hundreds of Indian and Chinese traders who had gathered there.

Our lives are going to change once trade gets going Sonar Bhutia Sikkim trader In pictures: Historic opening Sikkim's old Silk Road

"We hope the reopening of the silk route will improve relations between the two countries," China's ambassador to India Sun Yuxi told the AFP news agency.

"Today the border is open for traders and we hope very soon it will be open for tourists. We are excited and feeling very good."

The BBC's South Asia correspondent, Navdip Dhariwal, says the reopening of the route signifies a huge leap forward in diplomacy and trade between both countries.

Local traders have welcomed the opening and say it will have a major impact on the regional economy.

"Our lives are going to change once trade gets going," a grocery supplier, Sonar Bhutia, is quoted as saying by the AFP news agency.

"We're hoping to profit by it."

But correspondents say the opening is more symbolic than substantive, with trade confined to some local goods.

India will import 15 items from China, including goat and sheep skins, yak tails and raw silk.

China, for its part, will import 29 items including tea, rice and spices.

"Trading will take place four days a week, Monday to Thursday," says Sikkim director of industries, Saman Prasad Subba.

Diplomatic triumph

Some analysts believe that trade through the land route could generate millions of dollars in trade eventually.

Both sides have put their bitter past behind them

But at the moment most agree that there are more immediate political benefits rather than economic.

"This resumption of border trade is more significant for Indian diplomacy, not for trade," says Jayantanuja Bandopadhyay, professor of international relations in Calcutta's Jadavpur University.

Sikkim is a former Buddhist kingdom that merged with India in 1975, a move that was opposed by China which lay claim to the state.

"By allowing trade through Nathu La, China has accepted Sikkim as part of India that it refused to do earlier," Mr Bandopadhyay says.

The Nathu La pass was closed in 1962 after war broke out between China and India.