Goals from Chrispine Sakulanda, Patson Daka and Fashion Sakala secured the victory for the Young Chipolopolo, a result that ends Zimbabwe’s participation in the competition.
But Zambia cannot be caught at the top of the group whatever happens there and will face the second-placed team in Group D in the semifinals.
Zambia led midway through the first half when forward Sakulanda converted from inside the box, and doubled their advantage 16 minutes from time when senior international Daka coolly finished. Sakala added a third late on.
The match in Group D between DR Congo and Comoros was suspended in the second half when there was a power failure at the stadium past the hour-mark.
DR Congo were leading 2-0 at the time thanks to goals from Ernest Sita and Nathan Lusuki. A decision on the outcome of the match will be made later on Sunday.
Monday will see the conclusion of Groups A and C with the final round of matches to be played in those two pools.
South Africa have already secured top spot in Group A as they take on Botswana at the Moruleng Stadium (kick-off 17h00 local; 15h00 GMT).
The South Africans have been dominant so far, scoring nine goals and conceding none, and they will be keen to take that form into the semifinals.
The other match is Group A is the battle for second between Swaziland and Lesotho that kicks-off at the same time at the Mogwase Stadium.
Lesotho were thumped 8-0 by South Africa in their opener but bounced back to keep a clean-sheet in their 1-0 win over Botswana.
Swaziland have looked a good team having defeated Botswana 2-0 and then narrowly lost 1-0 to South Africa, conceding a late goal two minutes from time.
Before that, Angola and Mauritius are involved in a do-or-die clash for top spot of Group C (kick-off 14h00 local; 12h00 GMT).
Angola need just a draw to advance but if islanders Mauritius get the win they will leapfrog their opponents to top spot in the pool.
North African guest nation Sudan and opponents Seychelles are out of the running for the semifinals and will be playing for pride at the Mogwase Stadium.
Zambia 3 (Chrispine Sakulanda 25’, Patson Daka 74’, Fashion Sakala 86’) Malawi 0
SUSPENDED – Comoros 0 DR Congo 2 (Ernest Sita 6’, Nathan Lusuki 62’)
Group C – KO: 14h00 (12h00 GMT):
Sudan vs Seychelles – Mogwase Stadium
Mauritius vs Angola – Moruleng Stadium
Group A – KO: 17h00 (15h00 GMT)
Lesotho vs Swaziland – Mogwase Stadium