Mumbai, Dec 2 (PTI) Maharashtra on Thursday amended its air travel rules making seven-day institutional quarantine mandatory for passengers from only three countries -- South Africa, Botswana and Zimbabwe.Earlier, the state government"s November 30 order had made institutional quarantine mandatory for passengers arriving from all `at risk" countries in the central government"s list in view of the Omicron variant threat.Maharashtra Chief Secretary Debashish Chakravarty earlier in the day had said the state government was considering a revision of its guidelines, a day after the Centre wrote to the state saying its order was in divergence with the COVID-19 guidelines issued by the Union government. PTI MR KRK KRK