Russia switches to permanent summer time

• The clocks in all of Russia's nine time zones were moved forward one hour for the last time on Sunday under a decree President Dmitry Medvedev signed last month.
• Daylight saving time (DST) was introduced in the erstwhile Soviet Union in 1981 to reduce energy consumption by adjusting better to daylight differences in summer and winter.
• In contrast to countries that lie closer to the equator, such as India, where there is not much difference in the length of days and nights throughout the year, in Russia nights may last up to 16 hours in winter, leaving just eight hours for daylight in winter (less than one hour in the northernmost reaches), whereas in summer the proportion is reverse.
• Mr. Medvedev said the decision to switch to permanent summertime was made after studies showed that DST "disturbs the human biorhythm" and puts an unnecessary strain on public health.
• Some studies showed more suicides and heart attacks occur immediately after a shift to DST. Staying on summer time round the year will give people extra daylight in the afternoon during Russia's long winter. Critics said it would have been more logical to stay on winter time.
• They argued that Russia had already switched all its time zones one hour ahead under Joseph Stalin in 1930 and moved the clock further forward by one hour in 1981 when it went over to DST. This means that Russia will now be permanently two hours ahead of its original time zones.