Great Bengal Famine - 3 million dead - caused by the British Government in 1943
Bengal famine of 1770 - 10 million dead  - caused by British Rule (https://en.wikipedia.org/wiki/Great_Bengal_famine_of_1770)
Revolt of 1857 - 1 million Indians killed - British government
Algerian War - 1 million killed by the French
Holocaust - 6 million killed by the Germans
German concentration camps - 6 million Slavs and gypsies killed
Soviet Gulags - 25 million killed
Native Americans  - millions killed (http://rationalwiki.org/wiki/American_Indian_Genocide)

Want me to go on?