The Chinese GP has been postponed due to concerns over the Corona virus outbreak.

The race was scheduled to take place on 17-19 April but has been put on hold due to the Corona virus which originated in Wuhan in China.
A Formula 1 statement said:
“The Chinese Grand Prix has always been a very important part of the F1 calendar and the fans are always incredible. We all look forward to racing in China as soon as possible and wish everyone in the country the best during this difficult time.”
This means there will be a three week gap in the calendar between the Vietnam and Dutch GP’s.