This Metrodecker is a part of the 107 Metrodecker EVs (electric vehicles) order Optare has received since the product was launched 18 months ago, Ashok Leyland said in a statement.
First York launched the first of the battery-electric Optare Metrodecker EV double-deckers on July 30, it added.
The whole batch of 21 will be delivered by the end of September, it added.
Each Metrodecker EV with First York can carry 98 passengers, although that capacity is currently restricted due to social distancing measures, it added.
"We are proud of the progress Optare has been making in developing sustainable solutions for public transport. Optare has the know-how, technology and experience to help cities with reducing emissions from buses.
"Optare continues to be a key piece in our overall strategy to be amongst the Top 10 CV makers globally," Ashok Leyland MD & CEO Vipin Sondhi said.
The Metrodecker EVs deliver a range in excess of 160 miles.
These have been developed from the prototype by Optare in a partnership with First York and the York City Council, which began three years ago.
They are made and fully assembled at an Optare's factory in Sherburn, the company said.