November 2018, Uber became a gold member of the Linux Foundation. On May 10, 2019, Uber became a public company via an initial public offering. In June 2019, both COO Barney Harford and CMO Rebecca Messina stepped down. In July 2019, the marketing department was reduced by a third, with the layoff of 400 people amid continued losses. Engineer hires were frozen. In early September 2019, Uber laid off an additional 435 employees with 265 coming from the engineering team and another 170 from the product team. In October 2019, in partnership with HeliFlight, Uber offered 8-minute helicopter flights between Manhattan and John F. Kennedy International Airport for $200-$225 per passenger. Between October 2019 and May 2020, Uber offered Uber Works, a mobile app connecting workers who wanted temporary jobs with businesses in Chicago and Miami. In 2020, Uber announced plans to become an emission-free platform. Uber introduced Uber Green, promoting users to choose electric and hybrid vehicles. In January 2020, Uber acquired Careem for $3.1 billion. In the same month, Uber sold its Indian Uber Eats operations to Zomato, in exchange for 9.99% of Zomato. Also in January 2020, Uber tested a feature that enabled drivers at the Santa Barbara, Sacramento, and Palm Springs airports to set fares based on a multiple of Uber's rates for UberX and UberXL trips. On May 5, 2020, during the COVID-19 pandemic, Uber announced plans to lay off 3,700 employees, around 14% of its workforce. On May 18, 2020, 3,000 more job cuts and 45 office closures were announced. In June 2020, Uber announced that it would manage the on-demand high-occupancy vehicle fleet for Marin Transit, a public bus agency in Marin County, California. This partnership is Uber's first SaaS partnership. In July 2020, Uber, in partnership with its majority-owned Cornershop, launched Uber grocery delivery service in Latin America, Canada, Miami, and Dallas. On December 1, 2020, Uber acquired Postmates for $2.65 billion. In December 2020, Uber sold its Elevate division, which was developing short flights using VTOL aircraft, to Joby Aviation. In January 2021, Uber ATG/Advanced Technologies Group, a joint venture minority-owned by SoftBank Vision Fund, Toyota, and Denso that was developing self-driving cars, was sold to Aurora Innovation for $4 billion in equity and Uber invested $400 million into Aurora. In March 2021, the company moved to a new headquarters on Third Street in Mission Bay, San Francisco, consisting of several