China's economic growth for 2017 was 6.8% and India's was 6.7%. That means both economies are doing well, right? Not quite.
Firstly, India's population is growing. About 1% of India's economic growth comes solely from population growth, which is not sustainable. Indian cities are already overcrowded.
Secondly, the quality of the growth means India will hit a wall economically.
Take a look at Forbe's chart of China's and India's top export categories (see below).
China's top export categories are computers, telecommunications equipment, telephones, integrated circuits, and light fixtures (LEDs?). These are high value-added products.
China is expanding into consumer and military drones, computer memory chips (3D NAND and DRAM), passenger jet aircraft, industrial robots, AI, self-driving cars, electric vehicles, etc. These are also high-value products.
China's future economic expansion makes a lot of sense and it's all high-tech.
However, India's top export categories are refined petroleum, diamonds, jewelry, packaged medicines, and automobiles. Aside from automobiles (or is it really auto parts?), there is no place for India to go. Indian exports are mostly low-tech with no room for expansion. For example, diamonds and jewelry are not scalable (which is very different from computer DRAM chips).
In conclusion, while India may grow economically at 6.7% for a few more years, it will eventually slam into an immovable economic wall. There is limited demand for diamonds and jewelry. This phenomenon is typically called the "low income trap" or the "middle income trap."
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India Will Outgrow China In 2018, But Must Invest In Next-Generation Value Chains To Succeed | Forbes (January 2, 2018)
"The real long-term challenge for India isn't the size of its exports, but the structure of its exports.
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To see India's challenge, just look at its top export industries: petrochemicals and jewelry....India's second big export industry is finished jewelry, which like petrochemicals is a one-time value-add play with no potential to power real economic transformation.
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It is difficult to see how India could break into -- let alone climb -- the kinds of major global value chains that could bring truly transformative economic growth."