Buddhism is a Religion
But it is widely regarded as
an atheistic religion. Buddhist scriptures either do not promote or actively reject the existence of a creator god, the existence of "lesser" gods who are the source of morality, and that humans owe any duties to any gods. At the same time, though, these scriptures accept the existence of supernatural beings which might be described as gods. Some Buddhists today believe in the existence of such beings and are theists. Others dismiss these beings and are atheists.
Since there is nothing about Buddhism which requires belief in gods, atheism in Buddhism is easy to maintain.
The Jain Religion
For Jains, every soul or spiritual being is worthy of the exact same praise. Because of this, Jains do not worship any "higher" spiritual beings like gods nor do they worship or pay homage to any idols. Jains believe that the universe has always existed and will always exist, so there is no need for any sort of creator god. None of this means that no spiritual beings exist which might be called "gods," however, and thus a Jain might believe in beings which might be considered gods and therefore technically be a theist.
From a Western religious perspective, though, they'd all be atheists.
Atheism in Confucian & Taoist Religion:
On a functional level, at least, both Confucianism and Taoism can be considered atheistic. Neither is founded on faith in a creator god like Judeo-Christian Religions are. Neither promote the existence of such a god, either.
Atheism and religion are often portrayed and treated as polar opposites; although there is a strong correlation between being an atheist and being
irreligious, there is no necessary and inherent connection between the two. Atheism is not the same as being irreligious; theism is not the same as being religious. Atheists in the West tend not to belong to any religion,
but atheism is quite compatible with religion. If you are Adamant in your beliefs than you have a lot of Faith in your belief and are in effect a religious Atheist
Adapted aboutreligion.com