* 58,097 new infections, total at more than 35 mln

* First death in diabetic man, in western state of Rajasthan

* Auto manufacturing state announces one day lockdown on Sunday

* Officials say most cases mild, hospitals can still get pressured

NEW DELHI, Jan 5 (Reuters) - A diabetic man who died in the western state of Rajasthan was India's first fatality from the Omicron COVID-19 variant, the health ministry said on Wednesday, adding that overall infections had doubled to 58,097 over the past four days.

The health ministry reported that total Omicron infections had risen to at least 2,135, just over a month since the first case was detected in the country.

Government officials privately say daily cases in the country's third wave of infections could surpass the record of more than 414,000 hit last May. They also warn that many people are taking the Omicron variant lightly and not wearing masks as most cases have been mild.

Top health official Vinod Kumar Paul declined to estimate a new peak but said even mild cases could put pressure on the country's health systems.

"There is no room for complacency," he told a weekly media briefing, adding Omicron was driving surges in the cities. "Don't take it for granted. We don't know, the system can get overwhelmed, your household can get overwhelmed."

Nevertheless, the government reduced the number of home quarantine days for mild and asymptomatic patients to a week, from 10 or 14 days previously.

Another official at the briefing said the elderly man from Rajasthan, whom he did not identify by name, died of a heart attack a few days ago. Genetic tests later showed he had been infected by the Omicron variant.

ELECTION RALLY FEARS

Despite cases rising and restrictions on movement announced in several regions, political parties have continued to hold mass rallies ahead of state elections due in the next weeks and months.

Health authorities plan to meet election commission officials on Thursday over the matter, officials said, as private health experts raise concerns that the rallies would again lead to a big spike in cases, like in April and May last year.

On Wednesday, the southern state of Tamil Nadu, home to manufacturing plants of companies such as Renault-Nissan, Eicher Motors, Hyundai Motor, Caterpillar Inc and Foxconn, announced a one-day lockdown on Sunday and a daily night curfew, with some exceptions for industries.

Many other states or cities have also placed curfews and closed schools.

Experts, meanwhile, have called for hospitals to get ready.

"With infections expected to be skyrocketing we need: clear communication about self-care to prevent panic-driven trips to the hospitals," Bhramar Mukherjee, professor of epidemiology at the University of Michigan, wrote on Twitter.

"Scale up hospital capacity and optimise care to those who really need it," she said.

New Delhi's All India Institute of Medical Sciences cancelled a winter holiday for staff between Jan. 5 and 10. Many doctors and nurses have contracted the virus in recent days.

Authorities, especially in Delhi, have repeatedly said only those who need round-the-clock monitoring should go to hospital while others should recover at home.

Delhi tightened up virus mitigation measures on Tuesday, ordering people to stay home https://www.reuters.com/world/india/india-reports-most-covid-19-cases-since-early-september-2022-01-04 on the weekends, in addition to a night curfew.

India has had more than 35 million COVID-19 cases, the second highest tally after the United States. The health ministry reported 534 new deaths on Wednesday, taking that toll to 482,551. (Reporting by Krishna N. Das in New Delhi, Chandini Monnappa in Bengauluru and Sudarshan Varadhan in Chennai; Editing by Himani Sarkar, Robert Birsel)