According to RIA Novosti, via Bloomberg, the authorities have put the measures into place to combat alcohol addiction:
The authorities in the Far Eastern Siberian republic have been battling to curb excessive drinking for quite some time. In 2010, Yakutia's President Yegor Borisov introduced a similar ban, meaning spirits could only be sold between 2 p.m. and 8 p.m. That ban, however, didn't cover beer sales.
According to eYakutia, around 500 people die of alcohol intoxication every year in Yakutia. On average, Russians countrywide consume 32 pints of pure alcohol and an estimated 500,000 people die due to alcohol-related illnesses every year.
Since the Soviet times, when alcoholism was rampant, the Russian authorities have attempted to curb excessive drinking through taxation, public health campaigns, and limitations on sales. Experts believe alcohol is partly responsible for Russian men's low life expectancy of 60 years.
In Yakutia, it would seem that the earlier ban of 2010 didn't go so well:
Spanning three times zones, Yakutia is massive and is dotted with remote settlements, where enforcing such a ban will be a formidable challenge.
Now, with the only time to buy booze being in a chunk of the working day, one unintended consequence of the ban could be greater absenteeism.