country has stayed on UTC−03:00. Argentina is located at a longitude that would naturally put it in the UTC−04:00 or UTC−05:00 time zone. San Luis province, which was previously in a different time zone than most of the country and which formerly observed DST, decided in April 2010 not to change its clocks back and to stay on UTC−03:00 all year round. The most recent history of Argentina observing DST dates from 2007 to 2009. After a period of not observing DST, Argentina observed DST in some provinces in an attempt to save energy. For each period, the executive branch of the government set the specific start and end dates for DST, i.e. there was no fixed annual schedule. Bolivia In 2011, Bolivia planned to observe DST starting September 1 for the first time in its history, advancing the clock an hour on a nationwide basis in order to offset their energy problems. The schedule change was planned to take place every year between September and March, corresponding to the spring and summer of the South American country. However, the day before the scheduled change, on August 31, 2011, the national government indefinitely suspended the observation of DST due to opposition from experts in electricity, neighborhood and school leaders, and the general populace. Brazil Brazil adopted DST (called horário de verão—"summer time"—in Portuguese) for the first time in 1931, and it was in effect across the entire country. The duration and regional applicability of DST has varied over the years (see Portuguese Wikipedia page for details). As of 2013, DST was used only in the southern region (the states of Rio Grande do Sul, Santa Catarina, Paraná), the southeast region (the states of São Paulo, Rio de Janeiro, Espirito Santo, Minas Gerais), and the central-west region (the state of Goiás and the Distrito Federal, and the states of Mato Grosso and Mato Grosso do Sul). Formerly, starting and ending dates were variable, but in 2008, a decree (No. 6558 of 9 September 2008) established a permanent rule: DST starts at 00:00 on the third Sunday in October from 2008 to 2017 (and on the first Sunday in November from 2018 to the present), and ends at 00:00 on the third Sunday in February—unless the latter falls during Carnaval: in this case, the end of DST was postponed by one week. In 2019, Brazil scrapped daylight saving time and now stays