Urban populations generally benefit
from higher incomes and better access
to health care services compared with
rural areas, but disparities remain
between the rich and poor within cities.
Informal settlements and slums—which
house more than 1 billion of the world’s
urban dwellers—are often not equipped
with basic sanitation systems. Across
sub-Saharan Africa, more than half
of the urban population lives in areas
where access to basic infrastructure,
such as private toilets, is limited.9 One
study found that the child mortality rate
in Nairobi’s slums was far higher than
the rural child mortality rate