According to Turkish Airlines:
In accordance with coronavirus (Covid-19) pandemic measures, cabin baggage rules have been temporarily amended to maintain social distance and reduce movement around the cabin. At this time, one personal item per passenger, not to exceed 4 kg, is permitted in the aircraft cabin. One piece of cabin baggage per passenger, not to exceed 8 kg, will be carried in the cargo compartment free of charge.
How does reducing the amount of hand luggage reduce movement around the cabin or improve social distancing? Did Turkish Airlines (or other airline authorities) clarify how they've arrived at this policy? Do note that this seems to be a rare policy as of July 2020, as other airline seem to follow their normal hand luggage rules.