Three quarters of the 40 cities and towns surveyed across Ireland are clean, compared to just over half this time last year, according to Irish Business Against Litter (IBAL).
The final survey of 2022 shows that Naas in Co Kildare is the cleanest town in Ireland, with its Main Street singled out as "exceptionally well presented and maintained".
Kilkenny and Maynooth are in joint second.
For the third year in a row, Waterford was deemed the cleanest city, ahead of Galway.
Mahon in Co Cork is the only area in the country classified as "seriously littered", with An Taisce reporting dumping as an issue.
An Taisce said that "many sites were let down not just because of casual litter but due to presence of dumped items", such as dirty nappies.
The survey also showed little improvement in "littered" Cork city, which has a number of blackspots, such as Kennedy Quay, Carmelite Place/Western Road and the North Ring Road.
An Taisce reported "no let up on the dumping along this road - as well as bags of rubbish, there were larger household items e.g., chairs, white electrical appliances. It was in a very, very poor state."
IBAL spokesperson Conor Horgan welcomed the results and said they showed that "cleanliness in Ireland has returned to pre-pandemic levels, which is good because Covid saw litter levels rocket across the country".
Mr Hogan said there was a fear that the country "wouldn't return back to the progress that we'd been making over the years".
Speaking on RTÉ's Morning Ireland, he said some of the most "heavily littered sites" are seeing improvements in results.
"What is heartening to find is that we survey about 500 sites or 600 sites each time, we're constantly calling on local authorities to address the heavily littered sites because we find them time and again the same sites never being addressed, that seems to be changing," Mr Horgan said.
Naas volunteer thrilled at 'double whammy'
The Secretary of Naas Tidy Towns Committee said they are "absolutely thrilled" to be declared the cleanest town in Ireland.
Vourneen Hennessy told RTÉ's News at One that it is a "double whammy" as it is the second year in a row that Naas claimed the title.
"It's marvelous but I suppose we deserve it. We work hard and it’s a relentless task. As you know picking litter is just constant, so we just keep ploughing away and it’s great to be rewarded," she said.
There are around 55 regular volunteers with the group, which she says "all remain very positive, even though it is relentless".
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"I mean they never go out and litter pick and don’t find any. But they are very happy to do it and we wouldn’t win this award only for our volunteers and our TUS workers."
Ms Hennessy said disposable vapes are a common find in the town.
"At the moment it is the disposable vapes. And that comes with a mechanism, as well as a box and a list of instructions - so we get a lot of them.
"Cans and bottles continue to be picked, and masks not so much now and takeaway food - that's a constant," she added.
