In 1894, Thutob Namgyal, the Sikkimese monarch under British rule, shifted the capital from Tumlong to Gangtok, increasing the city's importance. A new grand palace along with other state buildings was built in the new capital. Following India's independence in 1947, Sikkim became a nation-state with Gangtok as its capital. Sikkim came under the suzerainty of India, with the condition that it would retain its independence, by the treaty signed between the Chogyal and the then Indian Prime Minister Jawaharlal Nehru. This pact gave the Indians control of external affairs on behalf of Sikkimese. Trade between India and Tibet continued to flourish through the Nathula and Jelepla passes, offshoots of the ancient Silk Road near Gangtok. These border passes were sealed after the Sino-Indian War in 1962, which deprived Gangtok of its trading business. The Nathula pass was finally opened for limited trade in 2006, fuelling hopes of economic boom.