On 16 March 2020, the Commission adopted Guidelines for border management measures to protect health and ensure the availability of goods and essential services.
On this basis, on 23 March 2020, the Commission adopted a Communication on the implementation of the Green Lanes under the Guidelines with specific recommendations designed to preserve the EU-wide operation of supply chains and ensure the functioning of the Single Market for goods, wherever internal border controls exist or have been introduced.
I blog posted about this at the time.
The European Commission issued (30th March) a Communication explicitly clarifying that the principles relating to transport of goods apply mutatis mutandis to shipments of waste.
This document is here.