On the western side, China had to face Kyrgyzstan, Tajikistan, Uzbekistan, Afghanistan, India, Nepal, Bhutan, and Bangladesh – eight nations in total.
One of them was China's biggest opponent, India. Its population was close to China's, and it would most likely surpass China's in the future. Right now, India's economy was not as developed, and its GDP was much lower.
Comparatively speaking, India's capital was like a small city in China – it was evident how far behind India's economy was. Moreover, India was a country with many religions, and many of them forbid abortion, which contributed to the boom in population.
On the other hand, China's population had been greatly restricted since recent times, and even though the Chinese population was greater at this moment in time, it was likely that India would surpass it in future, especially as its economy developed.