env.sls

{% set environments = salt['pillar.get']('php:environments', {}).items() %}
{% set processed_environments = [] %}


{% for env_name, env_val in environments %}
  {% do processed_environments.append('env['~ env_name ~'] = ' ~ env_val) %}
{% endfor %}

install_www_conf:
  file.managed:
    - name: /etc/php/7.0/fpm/pool.d/www.conf
    - source: salt://php/files/pool_www.jinja
    - template: jinja
    - defaults:
      environments: {{ processed_environments }}

my_pillar.sls

php:
  environment:
    ENV_VAR_1: test
    ENV_VAR_2: test2

output.txt

from minion:

sudo salt-call state.apply php.env
[INFO    ] Loading fresh modules for state activity
[CRITICAL] Rendering SLS 'base:php.env' failed: while parsing a flow sequence
  in "<string>", line 9, column 21:
          environments: [u'env[ENV_VAR_1] = asdd ...
                        ^
expected ',' or ']', but got '['
  in "<string>", line 9, column 27:
          environments: [u'env[ENV_VAR_1] = asddddddd ...
                              ^
local:
    Data failed to compile:
----------
    Rendering SLS 'base:php.env' failed: while parsing a flow sequence
  in "<string>", line 9, column 21:
          environments: [u'env[ENV_VAR_1] = asdd ...
                        ^
expected ',' or ']', but got '['
  in "<string>", line 9, column 27:
          environments: [u'env[ENV_VAR_1] = asddddddd ...