The Supreme Court on Thursday revoked 122 telecoms licences issued under a scandal-tainted 2008 sale, including 22 licences Telenor holds via Uninor, a joint venture with real estate firm Unitech.
Affected licence holders can operate for four months, during which regulators will come up with new market rules.
Asked whether Telenor should heed calls by several company investors and analysts to quit the Indian market now and cuts its losses, Jon Fredrik Baksaas said: "That is one alternative that is on the table."
"The ruling is a very serious attack on our investments, based on the licence framework that was spelt out in 2008," the chief executive said in an interview.
"We met every inch of that regulation of that licence. We have brought competition to the Indian market ... just to see a ruling that has significant retroactive consequences. It is an action that we have never seen in any country before."