"It is an unprecedented level of participation," an EU official said, adding that the biggest consultation so far took place in 2015 on the birds and habitat directive with 550,000 participants.

The commission will assess the answers on summertime in the next few weeks and decide whether to propose changing the legislation.

"It is not a referendum," the official added, saying the commission will take into account a variety of aspects, and not only the result of the consultation, which was launched on 4 July.

No conclusive evidence

In February the European Parliament adopted a non-binding resolution calling on the commission to carry out an assessment, and if necessary, come up with proposals for its revision.

"Numerous studies have failed to reach a conclusive outcome, but indicate negative effects on human health," MEPs said at the time.

Critics say the bi-annual time changes do not result in energy savings as originally intended, and are harmful to humans' biological rhythm, leading to long-term health problems.

But in the parliamentary debate EU transport commissioner Violeta Bulc was less than enthusiastic. "The evidence is conclusive only on one point," Bulc said. "That letting member states be free to apply uncoordinated time changes would be detrimental for the internal market."

Harmonised time

In all the EU's 28 member states the clocks go forward one hour in March for the summer, and back again in October for the winter, resulting in an 'extra' evening daylight hour during the warmer months and 'extra' morning daylight during winter.

The EU legislation lays down that member states cannot independently stop using the practice, there needs to be one system - either with one time or with the twice-annual adjustments.

The aim of the EU legislation was to unify existing national summertime schedules and to ensure a harmonised time switch within the single market.

Any changes to the EU legislation would require the approval of a majority of EU member states governments and the EP, a process that would likely to outlast the current EU commission's mandate.

So far Finland, Luxembourg, Estonia support abolishing the daylight-saving time. Earlier this year Finland gathered 70,000 signatures from citizens asking to abolish the rules.

The three countries only account for 1.45 percent of the EU population.

The EU has three time zones. The Greenwich mean time (GMT) is applied by the UK, Ireland, and Portugal. The Central European time (GMT+1) is used by 17 member states. The Eastern European time zone (GMT+2) is applied in eight EU members from Finland to Greece.