Scripture makes it clear that people are condemned by their actions, their sins, and this is known in one’s heart (see Rom. 2:14-15). In short, no one is ever condemned to hell because of not hearing the gospel. People are condemned for their sin.
God offers a “way out” to all people. No one is unaware that God exists, and the Bible is clear that man is accountable to Him (see Ps. 19; Rom. 1:18-2:12). Whether it is in faraway jungles or urban centers, God sends light to every person. The problem is that people reject the light they have been given.
For a more in-depth explanation, and how to respond when people ask this question, read: What About Those Who Have Never Heard of Jesus? Will They Be Condemned?