The problem statement or the project rationale section of the proposal defines the underlying situation existing in your project area. In this section, you explain why the project is necessary and how a grant funding will help address the existing human rights issues.
Now human rights can itself be such a broad area and if a donor agency has agreed to fund your organization, it means that the support will always be limited to a particular part of the overall human rights issue in the area. For example, if women and girls have remained illiterate because of which they have no knowledge of their rights, it is a human rights issue for women and girls. The NGO will work address this particular issue concerning with the women and girls in the community only and not for the whole community.
Similarly, if a particular community such an indigenous or tribal group of people who have been badly affected by a recent government policy on putting a general ban on the use of forest resources, your project will only address the problem of this community and not for all others who have been affected by the policy. The ban on access to forest resources may have impacted the tribal community in seeking out their livelihood and therefore, it is a human rights issue.
You can give a precise description of the situation in the problem statement/project rationale section of the proposal. The use of quotes, live examples, references, research data and press articles would be very helpful. These will give a strong backing to the argument you are making and will convince the donor agency in extending the grant to your organization.
An additional note in this section can also about other existing or previous projects working on the same issue for which you propose the project. It may not always be the case that you are the only one or the first entity to have identified and proposed this project. Previous efforts against the same issue need to be identified and presented. If these efforts had failed, you can outline the reasons of this and if they had succeeded, you need to come up with a plan as to how your project will add value to this prevailing success.