This is the 13515th most frequent Russian word.
населённых
"Populated" or "inhabited."
In this sentence, 'населённых' is used as an adjective modifying 'пунктов' (areas), indicating places inhabited by people.
В России много населённых пунктов с богатой историей.
In Russia, there are many populated areas with a rich history.
Here, 'населённые' describes 'районы' (regions), again showing that these areas are inhabited or populated.
Некоторые населённые районы требуют новых инфраструктурных проектов.
Some populated regions require new infrastructural projects.
'населённых' in this sentence qualifies 'территорий' (territories), giving the meaning of areas occupied by people.