Why are carbon nanotubes so strong?

Carbon nanotubes are so strong due to their high tensile strength resulting from the covalent bonds formed between individual carbon atoms. You can read about Nanotechnology in India – Origins, Uses, Developments in the given link.

Further readings:

1. Nano Mission – UPSC Nanotechnology Notes for Science & Technology
2. Science & Technology Notes For UPSC – General Science Notes