God does not send people to hell because they never heard of Christ. He sends people to hell because they have sinned. The judgment for sin will be in relationship to how much they knew. To phrase it another way, it is action in light of privilege. A person living in England has maximum spiritual privilege. Therefore the spiritual standard for England would be the gospel of Jesus and everything in the Old and New Testaments. But someone who grew up in an uncivilized jungle might be held to account for the fact that something in his conscience told him there is a Creator worthy of his worship.
The Bible says his conscience will either accuse him or excuse him on the day of Jesus Christ (see Romans 2:14-16). God is not going to condemn people if their own consciences excuse them. Regretfully, every human being has sinned against his or her own conscience.
God does not judge people for failure to believe in Jesus, but because they are sinners. The problem is that “all have sinned and fall short of the glory of God” (Romans 3:23). For those who have received Jesus Christ as Saviour, there will be forgiveness and mercy.