From _____ year, France will impose green tax on plane tickets to fund less-polluting transportation projects ?

1) 2022
2) 2020
3) 2021
4) 2023

Explanation:
On July 9, 2019, With an aim to fund less-polluting transportation projects, French government announced to impose green tax up to €18 ($20) on plane tickets for all outgoing flights from airports in France with effect from 2020. Tax of €1.5 will be imposed on economy-class tickets on internal flights and those within Europe. The new measure is expected to bring €182 million a year which will be invested in greener transport infrastructures.