Lithuania is subdivided into 71 constituencies and each elects one member of parliament, in addition to 70 selected according to proportional representation. According to the law on parliamentary elections, constituency sizes cannot stray more than 20 percent from the average.
However, according to MPs who brought the case to the Constitutional Court, the 20-percent variation rule means that the difference between most and least populous constituencies can be as big as 50 percent, giving disproportionately more weight to some voters.
The OSCE Office for Democratic Institutions and Human Rights recommends that the number of voters in each electoral district should not vary more than 10 percent from the average.
Depopulation due to migration has affected many rural areas in Lithuania, leaving some electoral constituencies much smaller than in more densely populated urban areas. The biggest constituency, Naujamiestis in Vilnius, currently has 50,000 voters, whereas certain rural districts have as few as 28-29,000.
The Central Electoral Commission has proposed redrawing district boundaries to redress the imbalance, but the proposal was met with resistance from a number of politicians.