At least four people died after a building collapsed in the financial capital Mumbai, and another 14 were killed in four landslides in other parts of Maharashtra
Cyclone Tauktae battered swathes of the vast nation, sending huge waves crashing onto its shores, turning streets into rivers and forcing hundreds of thousands of people to flee.
Moody's also echoed concerns raised by Barclays that a shortage of vaccines and India's population of nearly 1.4 billion could slow progress of the vaccine rollout.
After a lockdown a year ago caused widespread misery and one of the sharpest downturns of any major economy, the central government is desperate to avoid a hugely unpopular second shutdown.
India needs to crank up the pace of immunisation at home as it has so far inoculated more than 12 million people. It wants to vaccinate 300 million people - a fifth of its population - against the virus by August.
It makes 60% of all vaccines in the world and has gifted or sold COVID-19 shots to several countries.
GM's comments came after authorities in Maharashtra earlier this week rejected the automaker's application to cease operations at its plant in the western Indian state amid protests by workers.
In January 2020, it agreed to sell its second factory in the state's Talegaon district to Chinese automaker Great Wall Motor Co.