I am trying to use environment variables in an if statement in dbt jinja.

{{
    config(
    materialized='incremental',
    
    pre_hook="
    {% if env_var('dbt_evar_curr_annual') == 'Y' %}
        Truncate {{this}}
    {% endif %}
    "
    )
}}


SELECT
    {% if env_var('dbt_evar_curr_annual') == 'Y' %}
    1 As ID,
    'annual' As NAME
    {% else %}
    2 As ID,
    {{env_var('dbt_evar_curr_annual')}} As NAME 
    {% endif %}
FROM DUAL

I could see that my final table is getting loaded with a row of values 2,Y. That means I am correctly passing environment variables correctly as follows.

dbt run -m test_if3 --vars {dbt_evar_curr_annual:Y}

Can You please help me understand what is issue with my if statement.