In fact, the population growth rate is more than two times that of China (1.2% vs 0.46%) . And if you add up countries like Pakistan (about 190m) and Bangladesh (about 160m), Chinese population is not the highest because HK, Taiwan , etc all not big populations.
"The current population of China is 1,382,755,039 as of Tuesday, July 26, 2016, based on the latest United Nations estimates.
China population is equivalent to 18.72% of the total world population.
China ranks number 1 in the list of countries by population."
"The current population of India is 1,327,823,291 as of Tuesday, July 26, 2016, based on the latest United Nations estimates.
India population is equivalent to 17.84% of the total world population.
India ranks number 2 in the list of countries by population."
http://www.worldometers.info/world-population/population-by-country/
"The current population of China is 1,382,755,039 as of Tuesday, July 26, 2016, based on the latest United Nations estimates.
China population is equivalent to 18.72% of the total world population.
China ranks number 1 in the list of countries by population."
"The current population of India is 1,327,823,291 as of Tuesday, July 26, 2016, based on the latest United Nations estimates.
India population is equivalent to 17.84% of the total world population.
India ranks number 2 in the list of countries by population."
http://www.worldometers.info/world-population/population-by-country/