Why did Gandhiji choose to break salt law? How was this accomplished through the Dandi March?

Why was salt chosen?

British imposed high taxes on salt and many other commodities. Gandhi chose to break the salt law because he felt salt was a basic necessity for every section of society, be it, rich, poor, brahmin, Dalits, etc. The monopoly over salt deprived the people of valuable village industry. It was also a way to gather wider discontent among the people as it affected a larger audience.

Dandi March:

In order to break salt law, Gandhiji started the Dandi March from Sabarmati Ashram and vowed to never return till independence from British rule was achieved. Gandhiji and his followers marched for over 240 miles from Sabarmati to the coastal town of Dandi where they broke the government law by gathering natural salt found on the seashore, and boiling sea water to produce salt.