**Core Concept**
The health index is a quantitative measure used to evaluate the overall health status of a population. It is a composite score that takes into account various health-related indicators, such as mortality rates, disease prevalence, and health service utilization.

**Why the Correct Answer is Right**
Health indices, such as the Human Development Index (HDI) and the Disability-Adjusted Life Years (DALYs), are used to assess the health status of populations. They provide a comprehensive view of the health situation, allowing for comparisons across regions and over time. These indices are calculated based on various indicators, including life expectancy, education, and income levels.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because health indices typically do not include environmental health indicators, such as air and water quality.
**Option B:** This option is incorrect because health indices usually focus on health outcomes rather than healthcare access or healthcare utilization.
**Option C:** This option is incorrect because health indices are not primarily used to evaluate the quality of healthcare services, although some indices may include indicators related to healthcare access and utilization.

**Clinical Pearl / High-Yield Fact**
It's essential to note that health indices can be used to track progress towards global health goals, such as the Sustainable Development Goals (SDGs). However, they have limitations, including the potential for data quality issues and the need for careful interpretation.

**Correct Answer:** A.