The final decision negotiated by the Uzbek and Tajik parties, not without strong involvement of the Communist Party, left these three largely Tajik-populated territories within the Turkic-populated Uzbek SSR. The Tajik SSR was created on 5 December 1929 as the home for most of the ethnic Tajiks in Soviet Central Asia within the boundaries of present-day Tajikistan. Nation-building for ethnic minorities In the 1920s and the 1930s, the policy of national delimitation, which assigned national territories to ethnic groups and nationalities, was followed by nation-building, attempting to create a full range of national institutions within each national territory. Each officially recognized ethnic minority, however small, was granted its own national territory where it enjoyed a certain degree of autonomy, in addition to national elites. A written national language was developed (if it had been lacking), national language planning was implemented, native teachers were trained, and national schools were established. This was always accompanied by native-language press and books written in the native language, along with other facets of cultural life. National elites were encouraged to develop and take over the leading administrative and Party positions, sometimes in proportions exceeding the proportion of the native population. With the grain requisition crises, famines; troubled economic conditions; international destabilization and the reversal of the immigration flow in the early 1930s, the Soviet Union became increasingly worried about the possible disloyalty of diaspora ethnic groups with cross-border ties (especially Finns, Germans and Poles), residing along its western borders. This eventually led to the start of Stalin's repressive policy towards them. Following the introduction of the Soviet passport system in 1932, each adult citizen's ethnicity () was necessarily recorded in their passport. Where parents' nationalities differed, a citizen was able to choose which nationality to register in their passport. This practice did not exist in the Russian empire and has been abolished in the Russian Federation, although it remains law in some former-Soviet republics, including Kazakhstan and Uzbekistan. The Bolsheviks’ plan was to identify the total sum of all national, cultural, linguistic, and territorial diversities under their rule and establish scientific criteria to identify which groups of people were entitled to the description of 'nation'. This task relied on the existing work of tsarist-era ethnographers and statisticians, as well as new research conducted under Soviet auspices. Because most people did not know what is meant by a nation, some of them simply gave names when