In 1929, Stalin’s efforts to collectivize agriculture were in full swing, and the Soviet Union suffered some of the severest famines and grain shortages of its history. These economic conditions, combined with the Bolsheviks’ repression of religion, made it doubly difficult for Jews to obtain matzah for Passover. Having fled the USSR the previous year, and thus well aware of the circumstances there, Joseph Isaac Schneersohn, rebbe of the Lubavitch Ḥasidim, enlisted a number of prominent rabbis and communal leaders in a plan to send matzah to Soviet Jews. Dovid Margolin tells of their efforts:
On the morning of March 6, 1929, [the German rabbi Meir] Hildesheimer met with the Soviet ambassador to Berlin, Nikolai Krestinsky, with the latter saying that the Soviet government had officially granted permission for 50 train cars of matzah to be imported to the Soviet Union. . . . [After weeks of further negotiations], the Soviet trade representative telephoned [the Latvian Jewish leader Mordechai] Dubin and told him that he had made a mistake, and if the wagons had not yet been sent to please hold off, as he was awaiting special instructions from Moscow. Dubin . . . refused to back down. . . . Three hours later the Soviet official [allowed] the first five wagons to proceed to their destinations.
In Riga, [where the matzah was baked and then shipped to the USSR], another five wagons were prepared immediately, but then came news from Berlin. The Soviets [would still allow] for 50 train-cars of matzah, but there was a catch: [the exporters] would need to pay the luxury duty of two rubles per kilogram. Each wagon could hold approximately 5,000 kilograms of matzah—250,000 kilograms all together. This brought the sum needed to approximately $130,000 in taxes alone, the equivalent of nearly $2 million in 2019.
Yet, after further negotiation and much last-minute fundraising, 28 of the 50 the train-cars made their way to the intended recipients.
Read more on Chabad.org: https://www.chabad.org/news/article_cdo/aid/4353455/jewish/The-1929-Struggle-to-Send-Matzah-into-the-Soviet-Union.htm