Why did Gandhiji decide to launch a nationwide Satyagraha against the proposed Rowlatt Act, 1919?

Gandhiji decided to launch a nationwide Satyagraha against the proposed Rowlatt Act, 1919, because:

1. It gave enormous power to the government and no power to the leaders.
2. This law was hurriedly passed even after the united opposition by the Indians and other Indian leaders.
3. It allowed the detention of political leaders without any trial for three years.
4. It means that the British Government can arrest any Indian leader without any proof of crime.