Surya is in 12th Bhav.  The 12th Bhav giving up. So  when Surya is in 12th, ego and kingship is given away. So  Gandhi ji never felt like a king.  Surya is in Virgo whose lord is mercury . Mercury is most nonviolent graha and believes ahimsa. He started non violent movement. 12 Bhav  is meditation and surya means Ram . He  gave meditation mantra ” Raghu pati raghav raja ram ” Meditating on Ram. 

12th Bhav has virgo rashi which is a natural sign for disputes and arguments. He created the disputes against foreigners. He used his speech and letters (mercurial trait) to create a disputed environment against Britishers.