The graph compares the populations of India and China from years 2000 to 2050.
While China’s population was higher in the 2000’s, the graph shows that India will pass China by the middle of the 21st century. In 2000, China’s population stood at around 1.25 billion, significantly higher than India’s 1 billion. Over the following decades, both countries experienced steady growth, but the rate of increase in India was constantly faster. By 2023, China’s population starts decreasing ans reached approximately 1.4 billion, whereas India’s continued to grow constantly.
Projections suggest that by 2030, India’s population will be equal to China’s, after which it will surpass it. While India’s population is expected to rise to nearly 1.7 billion by 2050, China’s population is estimated to decline around 1.35 billion.
To sum up everything that has been stated so far, 
the graph shows opposite population trends of China and India, with China’s growth stabilising and eventually decreasing, while India’s population continues to rise throughout the period.