The sentence "Population is bigger" is correct and usable in written English.
You can use it when you are discussing the size of a population compared to another population. For example, "The population of Mexico is bigger than the population of Guatemala."
(Its total population is bigger than Russia's).
The U.S. population is bigger now, and a dollar today isn't worth as much as a decade ago.
Ankara too has mushroomed out of nothing, to a point where its population is bigger than that of any other European capital except London, Moscow and Paris.
By 2050 the number of working-age people in Germany will be a lot smaller than in France or Britain, even though its overall population is bigger.
Oil was changing the state, and many residents were worried about what effects it would have: on the landscape, on the creatures that inhabited it, and on themselves".The Alaska population is bigger now, because of the pipeline," one native Alaskan told McPhee.
Given the myriad corporate announcements of job cuts and precipitous sales declines — and the fact that the U.S. population is bigger than it was seven years ago — the fact that we're going to be seeing half a million new jobless claims a week came as a surprise to no one.
"The population is big and young," said Mr. Baswedan.
"We have been really lucky that our Hispanic population is big enough to help us bridge this gap," McFadden said.
The population is big enough to support one complete district and half of another, but the Republicans in the Legislature didn't want that many Democrats buzzing in one hive, so they carved it up.
This was reported in bigger health facilities located in peri urban areas as expressed by one respondent: "The population is big and the drugs the government send us are not enough".
The Israeli population is big in NY and you will find plenty of consolidators advertising to this community for travel to Israel.
