Made since the election, the film uses news footage including the killing of Neda Agha-Soltan, who became a symbol of martyrdom for the cause of freedom and democracy in Iran.
In "Green Days," the central character Ava is a young woman suffering from depression who fails to catch the spark of enthusiasm for the elections. Rather, she heads out into the streets to seek dialogue with compatriots she sees as mere dreamers.
Neshat made her directorial debut Wednesday with "Women Without Men," dissecting Iranian society at the time of the 1953 CIA-backed coup that overturned the nationalist government of Mohammed Mossadegh and installed the Shah in power.
Against that backdrop, four women -- a prostitute, an activist, a cosmopolitan woman and a traditional young girl -- fight for individual freedom and independence, winding up together at an idyllic orchard in the countryside.
"The four characters are who I am -- every one of them carries some personal dilemma, though it is not exactly autobiographical," the young photographer and visual artist told reporters.
Based on a novel by Shahrnush Parsipur, the film vying for the prestigious Golden Lion here is dedicated to "those who lost their lives fighting for freedom and democracy in Iran, from the constitutional revolution of 1906 to the Green Movement of 2009."
Neshat said: "This film speaks to the Iranian people and the world. We have been struggling for over 100 years, and we will not give up. ... We will get there one day."
In the film, partisans of Mossadegh march in the streets before being crushed on the orders of Shah Mohammed Reza Pahlavi.
"Dictators have changed in form and shape and ideology, but the struggle for liberation still goes on," said Neshat, wearing green, the colour of the Iranian reformist movement.
Amirali Navaee has two short films in the festival, "As I Was Leaving My City" and "My Atomic Beloved."
In the first, the camera focuses on the legs of a dancing man, passing by those of a beggar, a sweeper, and someone who is being handcuffed by police.
"My Atomic Beloved" shows a young man rushing through the house of his ex-girlfriend 12 hours before an atomic bomb strikes Tehran.
The short films are part of the Venice Days section, which this year paid homage to the "resistance" of Iranian cinema.
The selection also includes "Muli," a black-and-white animation by Marjon Farsad, about a little girl who dreams of becoming a scientist but lives with the fear of "not being able to play again, one day."
Other Iranians featured in Venice are Hana Kamkar with "Shahrzad" and dissident Arash Irandoost with "Paper Airplane."
And for International Critics' Week, another Venice filmfest programme, Nader T. Homayoun offered his film noir "Tehroun" exploring the underbelly of the Iranian capital.
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