The Danish government has now decided that the construction of the tunnel under Fehmarn Belt will start in January 2021. It is expected to be opened in 2029.
Press release (in Danish): https://www.trm.dk/nyheder/2020/anlaegsarbejdet-paa-tunnelen-under-femern-baelt-saettes-i-gang/
Press release (in Danish): https://www.trm.dk/nyheder/2020/anlaegsarbejdet-paa-tunnelen-under-femern-baelt-saettes-i-gang/