Original: He toured with the IPO in the spring of 1990 for their first-ever performance in the Soviet Union, with concerts in Moscow and Leningrad, and toured with the IPO again in 1994, performing in China and India.
Simplified: He toured with the IPO in the spring of 1990 for their first-ever performance in the USSR, with concerts in Moscow and Leningrad, and toured with the IPO again in 1994, performing in China and India.