Reading the linked report by the Center for Legal Assistance to Pollution Victims [1], it's clear that the problem was not with the law being so complex it took 16 years to understand, but that the agencies tasked with enforcing the law were trying very hard to shirk their duty and stalling him at every opportunity. The People's Daily article [2] recounts a nice anecdote about getting rebuffed when requesting land use maps from the responsible agency, which he countered by quoting the law granting him access from memory, which apparently scared the agency employee enough to hand him the maps.

[1] http://www.clapv.org/english_lvshi/ZhiChiAnJian_Content.asp?...

[2] http://jx.people.com.cn/n2/2017/0203/c355185-29659118.html