I hate to break it to you but photojournalism is not a controlled environment most of the time. Your job as a photographer is to take something real and capture it for people who can’t be there.
In the case of natural disasters for instance, taking a photo of someone who is attempting to escape a flood of water has far more power then just photos of water. Look at this gallery and you will see what I mean.
While the photos with no people are not bad, they don’t have the same sort of impact as photos where there are people. The difference is in how you connect with people, and the emotion that is felt in the photo. These things are very important in photojournalism. The point of your photos is to connect people to the story and improve the stories being told in the text.
Thats why you should almost always focus on people in the situations you photograph. Making them the focus increases the amount of interaction you can get from your photos. We as a species focus on other humans, and if you can capture them in your photos you will have success and help tell the story of those you capture.