The Silk Route story: mules, wool and Jelep La

The main Kalimpong line ran north-east from the town through Pedong and Algarah, crossed into Sikkim near Rhenock, dropped to the river market at Rongli and then climbed hard to Zuluk, Nathang and Kupup before topping out at Jelep La, 4,270 m. On the Tibetan side it fell into the Chumbi Valley and continued over the plateau to Gyantse and Lhasa. A parallel line from Gangtok went over Nathu La, about 4 km north of Jelep La as the crow flies. Historically Nathu La served Gangtok and Jelep La served Kalimpong.

Altitudes below are approximate. The old caravans walked it in stages of a day each, resting their animals at grazing grounds that later became villages.

Even the pass name carries the route's character. The old Bengal District Gazetteer explains Jelep La as the lovely level pass, the easiest of the crossings between Sikkim and Tibet, which is why heavily loaded animals preferred it. The historian Alex McKay reads the Tibetan spelling differently, as a shepherd's bronze pass. Either way, it was a road built for animals, not wheels.

The trade is much older than the British, but they gave it roads and rules. The Treaty of Tumlong in 1861 made Sikkim a de facto British protectorate and abolished restrictions on travel and trade by British subjects. In 1873 J. W. Edgar, the Deputy Commissioner of Darjeeling, was sent to study the passes. He found active trade over Nathu La, but preferred Jelep La on physical grounds and recommended a road to it and a trade mart near it.

Work on a cart road towards Jelep La began in 1884. Tibet saw the road as a threat, and in 1886 a small Tibetan militia occupied ground around the pass. In 1888 the British sent a military expedition; there was fighting at Gnathang, today's Nathang Valley, in May 1888, and by September the British held the area around the pass again. Two years later, the 1890 Convention of Calcutta saw China recognise Sikkim as a British protectorate.

In 1903–04 Francis Younghusband led a British expedition to Lhasa with about 1,150 soldiers and more than 10,000 support staff and pack animals. Both Nathu La and Jelep La were used, with Nathu La becoming the main line of communication. In 1910 the 13th Dalai Lama travelled the other way, crossing Jelep La to escape a Chinese invasion and spending almost two years in Sikkim and Darjeeling.

Mules and horses were the trucks of this road. On the Gangtok–Nathu La line, a well-known account describes caravans of about 200 mules, each carrying roughly 80 kg, taking 20–25 days to reach Lhasa. Most of the trade in those last years was run by Marwari firms, which held the large majority of about 200 authorised trading licences.

The goods tell you what each side lacked. Going up to Tibet: pens, watches, cereals, cotton cloth, cooking oil, soap, building materials and, by the 1950s, scooters and cars taken apart to fit on mule-back. Coming down to India: raw wool, silk, musk pods, medicinal plants, precious stones, gold and silverware. Wool was the bulk of it, baled in Kalimpong and sent on down to the plains.

Kalimpong grew rich on this traffic. It drew Nepali, Tibetan, Bhutanese, Marwari and other traders, and even published the first Tibetan-language newspaper, the Tibet Mirror, from 1925. The town's mix of communities, schools and old trading families still reflects those years.

Bhutan had a stake too. The British granted the influential Dorji family of Bhutan a plot in Kalimpong, and Bhutan House became the channel for Bhutanese trade and relations through the town. Tibetan, Bhutanese and Sikkimese traders, British officials and Indian merchant houses all met in the same few streets.

The trade boomed in the 1950s. A motorable road from Gangtok towards Nathu La, built from 1954, was opened by Jawaharlal Nehru in the presence of the Chogyal on 17 September 1958, though it then ran only as far as Sherathang. For a few years, Calcutta was linked with Lhasa through the Chumbi Valley and these passes, and much of the trade between India and China passed this way.

Then the politics shifted. After the 1959 Tibetan uprising, the passes became a route for refugees fleeing south. During the 1962 Sino-Indian war there were clashes around Jelep La and Nathu La, and afterwards both passes were sealed. In 1967 serious clashes broke out at Nathu La and Cho La, with deaths on both sides. Kalimpong's trading economy slowed sharply, and the mule paths through Zuluk and Nathang went quiet except for army traffic.

After four decades, Nathu La was reopened for border trade on 6 July 2006. Indian traders use a designated mart at Sherathang, a few kilometres below the pass, and cross to a Tibetan mart on the other side. Trade runs on set days of the week, and weather limits it to roughly May to November. Volumes have stayed far below early hopes, and the list of permitted goods is short.

Jelep La remains closed, despite requests from Kalimpong's leaders for it to reopen. Below it lies Menmecho Lake, which is off limits to tourists. Twice a week at Sherathang, Indian and Chinese postmen still exchange mail bags at the border, a practice formally recognised by a 1992 agreement. Border rules change, so check current status before you travel.

Indian citizens can follow much of the old Kalimpong line on our Silk Route trips: Rhenock and Aritar, Rongli, the zigzag climb to Zuluk, the high valley at Nathang and the lakes near Kupup. You need a protected area permit beyond Rongli, and foreign nationals are not allowed on this stretch. Check current status before you travel.

A few things help the history come alive on the road.

• Stop at Rongli's market and picture it as a mule-train halt rather than a jeep stand.
• In Zuluk, ask your homestay host about the trading years; some village families still tell stories handed down from them.
• At Nathang, the open valley shows why caravans and armies camped here: water, grass and flat ground at 4,000 m.
• From the road near Kupup, the ridge to the south-east carries Jelep La. You cannot go there, but you can see where the road once went.
• Read Edgar's 1874 report or Younghusband's account before you go; both are out of copyright and online.