Why is conc.HNO3 transported in aluminium containers?

Concentrated nitric acid (HNO3) is transported in aluminum containers because aluminum is resistant to corrosion by nitric acid. Nitric acid is a strong oxidizing agent and can react with many metals, causing corrosion and potentially dangerous reactions. Aluminum, however, forms a protective oxide layer on its surface that prevents further reaction with the acid. This makes aluminum a suitable material for transporting concentrated nitric acid safely.