Meanwhile, supported by aid from China and the Soviet Union, North Vietnam strengthened its air defenses. By November 1967, the number of American troops in Vietnam was approaching 500,000, and U.S. casualties had reached 15,058 killed and 109,527 wounded.
India is one example of a subcontinent because it is a part of the Asian continent. Its landmass is not connected to the Asian continent plate, thus not part of it. India is regarded as the largest nation in South Asia and also known as the South Asian subcontinent. The term is used culturally and politically.
A place is classed as a subcontinent when it is part of a continent but is considered either geographically or politically as an independent entity or it is smaller than a continent. India is often called a subcontinent because it is a distinct landmass, not just a country. While it has many features of a continent, it is not as big as one, so is not considered a continent. India was once a continent (or at least a very large island). Due to continental drift, India moved north and became part of Asia.