Introduction. The XXI century is becoming not only an era of great discoveries and achievements, but also a time of extreme anthropogenic pressure the humans have on the various ecosystems. Alongside, the condition of all the natural components of the environment (water, forests, lands, air, etc.) deteriorates, which affects the human life and health, food quality, working and resting conditions. As soon as the state and society became aware about the danger of this trend, the various legal acts regulating the negative impact of the humans on the nature and containing a mechanism of ensuring the ecological rights of a person and a citizen began to be adopted. One of such ensuring mechanisms is the environmental liability institution, which envisages the liability of the environmental law breakers to be subject to the certain measures of the state coercion (of personal, property or organisational nature). The present article studies the efficiency of this mechanism.

   The aim of the paper is to investigate the general theory of legal liability for environmental offences, to express the authors' point of view on the debatable issues of improving the regulation thereof, as well as to demonstrate the dynamics of the environmental liability at the regional scale (in three Caspian regions).

   Materials and Methods. The research was carried out using the methods of scientific cognition commonly applied in Russia: general scientific (dialectical method) and specific scientific methods (analysis, synthesis, historical case-specific, logical, comparative legal, systemic methods and others).

   Results. Within the research the theory and practice of legal liability for environmental offences (in the frame of the criminal, administrative, civil laws) have been analysed. The authors have substantiated their point of view on the main debatable issues in the frame of each type of legal liability, expressed a number of critical comments regarding the concept of independent environmental liability, implying reparation of environmental damage. Cases of judicial practice for the regional level environmental offenses (in three Caspian regions of the Russian Federation — the Astrakhan region, theRepublics of Dagestan and Kalmykia) have been presented, the identified trends have been assessed.

   Discussion and Conclusion. The conducted research is important for the Russian legal science, since the efficiency of functioning the environmental liability institution is a condition for achieving the sustainable development goals and transition to the green economy, however its current state arises a number of doctrinal and practical issues. Among them could be distinguished: the insufficient activity of the Russian Federation subjects in development of the administrative liability sub-institution for the environmental offences, on-going problem of differentiation between the administrative and criminal liability, high latency of the environmental crimes, inefficient work of the law-enforcement authorities, insufficient elaboration of the issues of environmental damage reparation (e.g., harm to the health of citizens, compensation for the moral damage caused by the environmental offense, etc.). The study of judicial practice of three Caspian regions made it possible to conclude that within their boundaries there is no distinct specificity that would differ them completely from the other subjects of the Russian Federation having access to the sea or located in the large river basins. The same as in the other regions, the cases of soil, water and air pollution; poaching; the nature reserve protection regime violations; negligence of the owners towards the sunken vessels; restricted access to the shores of water bodies, etc. are quite widespread here. In these regions the specificity of liability lies not in the statistics of the separate offenses, but in the need to combat the environmental offences at the scale of the whole Caspian Sea, which requires coordination and political will of the Governments of all five littoral states (Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran).