each person must limit itself to or each person must limit themselves to
Hi everyone,
I have read an article about the drought in Cape Town, where the authorities are campaigning to curb water consumption. People have to limit themselves to 50 litres per person and per day.
In this context should I say
each person must limit itself to 50 litres of water per day
or
each person must limit themselves to 50 litres of water per day
Thank you for your help