Your 1st day of your notice period starts from the date you tender the resignation to your manager & HR. If your new employer stated they'll pay your 1-month salary in lieu, then so long as you fulfilled the 2-months including the public holidays and weekends, you are fine. In your case, 27th is a government public holiday, so you are supposed to be on holiday, but your salary is to be paid by your current employer. Ask HR to show you how they calculate your daily salary, I'm sure they'll likely tell you your monthly salary divided by 22 days. If that's the case, mean regardless of a public holiday that falls on weekdays, they'll have to pay your salary.