| Vulnerability class | DRASTIC Index |
| No | <61 |
| Externally very low | >61 - 80 |
| Very Low | >80 - 100 |
| Low | >100 - 120 |
| Moderate | >120 - 140 |
| High moderate | >140 - 160 |
| High | >160 - 180 |
| Very high | >180 - 200 |
| Extremely very high | >200 |