Yeah the problem is 50 Hz itself. All these electric digital clocks use the AC frequency as the clock sample frequency. In India, we do not get the constant 50 Hz. At some places the frequency is as low as 45 Hz while at some places is 50+ Hz. And this is not constant throughout the day.
Hence these digital clocks always loose or gain time.
A better (table) digital clock would be one with Quartz crystals.
Oh, if the frequency differs by 10 %, then my alarm clock would go 2.4 hours too slow per day.
That's a pretty major discrepancy. More reason to switch to battery operated quartz clock.
Do these radio controlled clocks work in India? They'd be even more reliable than quartz clocks. But I'm not sure about the international infrastructure for the senders.