Food security has three dimensions - availability, accessibility, and affordability of food. Food insecurity most affects the poor, landless, artisans, petty workers, and ill-paid urban occupations. Food security is ensured when enough food is available and accessible to all at an affordable price. Natural calamities and crop failures can threaten food security by reducing production and increasing prices, potentially leading to starvation and famine over the long term. India aims to ensure food security through self-sufficiency, public distribution systems, and welfare programs.