by opening outlets/shops in the second-tier cities.
Second tier cities are "spatially distinct areas of economic activity
where a specialized set of trade-oriented industries takes root and
flourishes, establishing employment and population-growth
trajectories that are the envy of many other places."
In other words, second tier cities are cities other than metropolises,
where growth is taking place. As many companies from the
developed world try to take advantage of globalization by
setting up businesses/offices in developing countries, the
cost of setting up and running businesses in metropolises is
going up, and so they open offices in second tier cities to
cut overhead expenses and to find local talent (from in and
around second tier cities). As businesses flourish and
provide employment to the local people in second tier cities,
their purchasing power goes up and new businesses (such
as retail, in this case) can cash in on that by opening outlets
in those cities.
I hope this explanation is not confusing.