3. Is there a ban on corporate donations to political parties?

Election Act 2017, section 204,

Relevant sections of Election Act,2017 are quoted here.
Membership fee, contributions and donations.—(1) A member of a political party shall be required to pay a membership fee, if provided in the political party‘s constitution and may, in addition, make contributions or
donations towards the political party‘s funds.
 (2) The fee, contribution or donation made by a member or a supporter of a political party shall be duly recorded by that political party.
 (3) Any contribution or donation made, directly or indirectly, by any foreign source including any foreign government, multi-national or public or private company, firm, trade or professional association or individual shall beprohibited.
 (4) Any contribution or donation which is prohibited under this Act shall be confiscated in favour of the Government in such manner as may be prescribed.