How is India's GDP 36x more than Sri Lanka but it's still called lower-middle-income?

India's GDP hit $3.96 trillion in 2025, 36 times Sri Lanka's $108.83 billion, according to World Bank data. Despite this, World Bank categorised Sri Lanka as an upper-middle-income economy while keeping India a lower-middle-income country. This is because the categorisation is based on gross national income/capita, which is affected by India's population, which is 63 times that of Sri Lanka.