There are several reasons why China cannot attack India:

1. International laws and norms: Attacking another country is generally considered a violation of international law and can lead to consequences such as sanctions and condemnation from the international community.
2. Military capabilities: While China may have a larger military, India has a strong military with significant defensive capabilities. An attack on India could lead to a costly and prolonged conflict for China.
3. Diplomatic relations: Both India and China are major powers and have diplomatic relations with each other. An attack on India would likely lead to a breakdown in these relations and could have negative consequences for China’s global standing.
4. Economic considerations: India and China are both major economies and trade partners. An attack on India could lead to economic disruptions and negative consequences for China’s own economy.
5. Domestic considerations: An attack on India could lead to public discontent within China and potentially destabilize the country’s internal political situation.

Overall, while China may have the military power to attack India, the potential consequences of such an action make it unlikely that it would actually do so.